The kilogram or kilogramme is the base unit of mass in the International System of Units. Until 20 May 2019, it remains defined by a platinum alloy cylinder, the International Prototype Kilogram, manufactured in 1889, stored in Saint-Cloud, a suburb of Paris. After 20 May, it will be defined in terms of fundamental physical constants; the kilogram was defined as the mass of a litre of water. That was an inconvenient quantity to replicate, so in 1799 a platinum artefact was fashioned to define the kilogram; that artefact, the IPK, have been the standard of the unit of mass for the metric system since. In spite of best efforts to maintain it, the IPK has diverged from its replicas by 50 micrograms since their manufacture late in the 19th century; this led to efforts to develop measurement technology precise enough to allow replacing the kilogram artifact with a definition based directly on physical phenomena, now scheduled to take place in 2019. The new definition is based on invariant constants of nature, in particular the Planck constant, which will change to being defined rather than measured, thereby fixing the value of the kilogram in terms of the second and the metre, eliminating the need for the IPK.
The new definition was approved by the General Conference on Weights and Measures on 16 November 2018. The Planck constant relates a light particle's energy, hence mass, to its frequency; the new definition only became possible when instruments were devised to measure the Planck constant with sufficient accuracy based on the IPK definition of the kilogram. The gram, 1/1000 of a kilogram, was provisionally defined in 1795 as the mass of one cubic centimetre of water at the melting point of ice; the final kilogram, manufactured as a prototype in 1799 and from which the International Prototype Kilogram was derived in 1875, had a mass equal to the mass of 1 dm3 of water under atmospheric pressure and at the temperature of its maximum density, 4 °C. The kilogram is the only named SI unit with an SI prefix as part of its name; until the 2019 redefinition of SI base units, it was the last SI unit, still directly defined by an artefact rather than a fundamental physical property that could be independently reproduced in different laboratories.
Three other base units and 17 derived units in the SI system are defined in relation to the kilogram, thus its stability is important. The definitions of only eight other named SI units do not depend on the kilogram: those of temperature and frequency, angle; the IPK is used or handled. Copies of the IPK kept by national metrology laboratories around the world were compared with the IPK in 1889, 1948, 1989 to provide traceability of measurements of mass anywhere in the world back to the IPK; the International Prototype Kilogram was commissioned by the General Conference on Weights and Measures under the authority of the Metre Convention, in the custody of the International Bureau of Weights and Measures who hold it on behalf of the CGPM. After the International Prototype Kilogram had been found to vary in mass over time relative to its reproductions, the International Committee for Weights and Measures recommended in 2005 that the kilogram be redefined in terms of a fundamental constant of nature.
At its 2011 meeting, the CGPM agreed in principle that the kilogram should be redefined in terms of the Planck constant, h. The decision was deferred until 2014. CIPM has proposed revised definitions of the SI base units, for consideration at the 26th CGPM; the formal vote, which took place on 16 November 2018, approved the change, with the new definitions coming into force on 20 May 2019. The accepted redefinition defines the Planck constant as 6.62607015×10−34 kg⋅m2⋅s−1, thereby defining the kilogram in terms of the second and the metre. Since the second and metre are defined in terms of physical constants, the kilogram is defined in terms of physical constants only; the avoirdupois pound, used in both the imperial and US customary systems, is now defined in terms of the kilogram. Other traditional units of weight and mass around the world are now defined in terms of the kilogram, making the kilogram the primary standard for all units of mass on Earth; the word kilogramme or kilogram is derived from the French kilogramme, which itself was a learned coinage, prefixing the Greek stem of χίλιοι khilioi "a thousand" to gramma, a Late Latin term for "a small weight", itself from Greek γράμμα.
The word kilogramme was written into French law in 1795, in the Decree of 18 Germinal, which revised the older system of units introduced by the French National Convention in 1793, where the gravet had been defined as weight of a cubic centimetre of water, equal to 1/1000 of a grave. In the decree of 1795, the term gramme thus replaced gravet, kilogramme replaced grave; the French spelling was adopted in Great Britain when the word was used for the first time in English in 1795, with the spelling kilogram being adopted in the United States. In the United Kingdom both spellings are used, with "kilogram" having become by far the more common. UK law regulating the units to be used when trading by weight or measure does not prevent the use of either spelling. In the 19th century the French word kilo, a shortening of kilogramme, was imported into the English language where it has been used to mean both kilogram and kilometre. While kilo is acceptable in many generalist texts
Irkutsk is the administrative center of Irkutsk Oblast and one of the largest cities in Siberia. Many distinguished Russians were sent into exile in Irkutsk for their part in the Decembrist revolt of 1825, the city became an exile-post for the rest of the century; some of the fine wooden houses still survive. When the railway reached Irkutsk, it had earned the nickname of "The Paris of Siberia." The city saw bitter fighting in the Russian Civil War of 1918-20, became a major centre of aircraft manufacture. Trans-Siberian Highway and Trans-Siberian Railway connect Irkutsk to other regions in Russia and Mongolia. Irkutsk was named after the Irkut River, whose name was derived from the Buryat word for "spinning" and was used as an ethnonym among local tribes as Yrkhu, Irkit and Irgyt; the city was known as "Yandashsky" after the local Tuvan chief Yandasha Gorogi. The old spelling of the name of the city was «Иркуцкъ». Before the revolution, the city was called "East Paris", "Siberian Petersburg", "Siberian Athens".
Locals like to think of their city as "middle of earth". In 1652, Ivan Pokhabov built a zimovye near the site of Irkutsk for gold trading and for the collection of fur taxes from the Buryats. In 1661, Yakov Pokhabov built an ostrog nearby; the ostrog gained official town rights from the government in 1686. The first road connection between Moscow and Irkutsk, the Siberian Route, was built in 1760, benefited the town economy. Many new products imported from China via Kyakhta, became available in Irkutsk for the first time, including gold, fur, wood and tea. In 1821, as part of the Mikhail Speransky's reforms, Siberia was administratively divided at the Yenisei River and Irkutsk became the seat of the Governor-General of East Siberia. In the early 19th century, many Russian artists and nobles were sent into exile in Siberia for their part in the Decembrist revolt against Tsar Nicholas I. Irkutsk became the major center of intellectual and social life for these exiles, much of the city's cultural heritage comes from them.
By the end of the 19th century, there was one exiled man for every two locals. People of varying backgrounds, from members of the Decembrist uprising to Bolsheviks, had been in Irkutsk for many years and had influenced the culture and development of the city; as a result, Irkutsk became a prosperous cultural and educational center in Eastern Siberia. In 1879, on July 4 and 6, the palace of the Governor General, the principal administrative and municipal offices and many of the other public buildings were destroyed by fire, the government archives, the library and the museum of the Siberian section of the Russian Geographical Society were ruined. Three-quarters of the city was destroyed, including 4,000 houses. However, the city rebounded, with electricity arriving in 1896, the first theater being built in 1897 and a major train station opened in 1898; the first train arrived in Irkutsk on August 16 of that year. By 1900, the city had earned the nickname of "The Paris of Siberia." During the Russian Civil War, which broke out after the October Revolution, Irkutsk became the site of many furious, bloody clashes between the "Whites" and the "Reds".
In 1920, Aleksandr Kolchak, the once-feared commander of the largest contingent of anti-Bolshevik forces, was executed in Irkutsk, which destroyed the anti-Bolshevik resistance. Irkutsk was the administrative center of the short-lived East Siberian Oblast, which existed from 1936 to 1937; the city subsequently became the administrative center of Irkutsk Oblast after East Siberian Oblast was divided into Chita Oblast and Irkutsk Oblast. During the communist years, the industrialization of Irkutsk and Siberia in general was encouraged; the large Irkutsk Reservoir was built on the Angara River between 1950 and 1959 in order to facilitate industrial development. The Epiphany Cathedral, the governor's palace, a school of medicine, a museum, a military hospital and the crown factories are among the public institutions and buildings; the Aleksandr Kolchak monument, designed by Vyacheslav Klykov, was unveiled in 2004. On July 27, 2004, the Irkutsk Synagogue was gutted by a conflagration. In December 2016, 74 people in Irkutsk died in a mass methanol poisoning.
In 2018, it was reported men in Irkutsk only survive on average to 63. Irkutsk is located about 850 kilometres to the south-east of Krasnoyarsk, about 520 kilometres north of Ulaanbaatar, the capital of Mongolia; the city proper lies on the Angara River, a tributary of the Yenisei, 72 kilometers below its outflow from Lake Baikal and on the bank opposite the suburb of Glaskovsk. The river, 580-meter wide, is crossed by the Irkutsk Hydroelectric Dam and three other bridges downstream; the Irkut River, from which the town takes its name, is a smaller river that joins the Angara directly opposite the city. The main portion of the city is separated from several landmarks—the monastery, the fort and the port, as well as its suburbs—by another tributary, the Ida River; the two main parts of Irkutsk are customarily referred to as the "left bank" and the "right bank", with respect to the flow of the Angara River. Irkutsk is situated in a landscape of rolling hills within the thick taiga, typical in Eastern Siberia.
The population has been shrinking: 587,891 .
Vladivostok is a city and the administrative center of Far Eastern Federal District and Primorsky Krai, located around the Golden Horn Bay, not far from Russia's borders with China and North Korea. The population of the city as of 2017 was 606,589, up from 592,034 recorded in the 2010 Russian census. Harbin in China is about 515 kilometres away, whilst Sapporo in Japan is about 775 kilometres east across the Sea of Japan; the city is the home port of the Russian Pacific Fleet and the largest Russian port on the Pacific Ocean. Vladivostok was first named in 1859 along with other features in the Peter the Great Gulf area by Nikolay Muravyov-Amursky; the name first applied to the bay but, following an expedition by Alexey Shefner in 1860, was applied to the new settlement. In Chinese, the place where the city is situated nowadays has been known since the Qing Dynasty as Haishenwai, from the Manchu Haišenwai or "small seaside village"; as the Manchu Qing Dynasty banned Han Chinese from most of Manchuria, it was only visited by shēnzéi who illegally entered the area seeking ginseng or sea cucumbers.
From this comes the Chinese name for the city, Hǎishēnwǎi. In modern-day China, Vladivostok is known by the transliteration 符拉迪沃斯托克, although the historical Chinese name 海參崴 is still used in common parlance and outside mainland China to refer to the city. According to the provisions of the Chinese government, all maps published in China have to bracket the city's Chinese name; the modern-day Japanese name of the city is transliterated as Urajiosutoku. The city was written in Kanji as 浦塩斯徳 and shortened to Urajio ウラジオ. In Korean, the name is transliterated as Beulladiboseutokeu in South Korea, Ullajibosŭttokhŭ in North Korea and China; the aboriginals of the territory on which modern Vladivostok is located are the Udege minority, a sub-minority called the Taz which emerged through members of the indigenous Udege mixing with the nearby Chinese and Hezhe. The region had been part of many states, such as the Mohe, Balhae Kingdom, Liao Dynasty, Jīn Dynasty, Yuan Dynasty, Ming Dynasty, Qing Dynasty and various other Chinese dynasties, before Russia acquired the entire Maritime Province and the island of Sakhalin by the Treaty of Beijing.
Qing China, which had just lost the Opium War with Britain, was unable to defend the region. The Manchu emperors of China, the Qing Dynasty, banned Han Chinese from most of Manchuria including the Vladivostok area —it was only visited by illegal gatherers of ginseng and sea cucumbers. On June 20, 1860, the military supply ship Manchur, under the command of Captain-Lieutenant Alexey K. Shefner, called at the Golden Horn Bay to found an outpost called Vladivostok. Warrant officer Nikolay Komarov with 28 soldiers and two non-commissioned officers under his command were brought from Nikolayevsk-on-Amur by ship to construct the first buildings of the future city; the Manza War in 1868 was the first attempt by Russia to expel Chinese from territory. Hostilities broke out around Vladivostok when the Russians tried to shut off gold mining operations and expel Chinese workers there; the Chinese resisted a Russian attempt to take Ashold Island and in response, two Russian military stations and three Russian towns were attacked by the Chinese whom the Russians failed to oust.
An elaborate system of fortifications was erected between the late 1890s. A telegraph line from Vladivostok to Shanghai and Nagasaki was opened in 1871; that same year a commercial port was relocated to Vladivostok from Nikolayevsk-on-Amur. Town status was granted on April 22, 1880. A coat of arms, representing the Siberian tiger, was adopted in March 1883; the first high school was opened in 1899. The city's economy was given a boost in 1916, with the completion of the Trans-Siberian Railway, which connected Vladivostok to Moscow and Europe. After the October Revolution, the Bolsheviks took control of Vladivostok and all the Trans-Siberian Railway. During the Russian Civil War they were overthrown by the White-allied Czechoslovak Legion, who declared the city to be an Allied protectorate. Vladivostok became the staging point for the Allies' Siberian intervention, a multi-national force including Japan, the United States, China; the intervention ended in the wake of the collapse of the White Army and regime in 1919.
In April 1920, the city came under the formal governance of the Far Eastern Republic, a Soviet-backed buffer state between the Soviets and Japan. Vladivostok became the capital of the Japanese-backed Provisional Priamurye Government, created after a White Army coup in the city in May 1921; the withdrawal of Japanese forces in October 1922 spelled the end of the enclave, with Ieronim Uborevich's Red Army taking the city on October 25, 1922. As the main naval base of the Soviet Pacific Fleet, Vladivostok was closed to foreigners during the Soviet years; the city hosted the summit at which Leonid Brezhnev and Gerald Ford conducted the Strategic Arms Limitation Talks in 1974. At the time, the two countries decided quantitative limits on nuclear weapons systems and banned the construction of new land-based ICBM launchers. In 2012, Vladivostok hosted the 24th APEC s
Moscow is the capital and most populous city of Russia, with 13.2 million residents within the city limits, 17 million within the urban area and 20 million within the metropolitan area. Moscow is one of Russia's federal cities. Moscow is the major political, economic and scientific center of Russia and Eastern Europe, as well as the largest city on the European continent. By broader definitions, Moscow is among the world's largest cities, being the 14th largest metro area, the 18th largest agglomeration, the 14th largest urban area, the 11th largest by population within city limits worldwide. According to Forbes 2013, Moscow has been ranked as the ninth most expensive city in the world by Mercer and has one of the world's largest urban economies, being ranked as an alpha global city according to the Globalization and World Cities Research Network, is one of the fastest growing tourist destinations in the world according to the MasterCard Global Destination Cities Index. Moscow is the coldest megacity on Earth.
It is home to the Ostankino Tower, the tallest free standing structure in Europe. By its territorial expansion on July 1, 2012 southwest into the Moscow Oblast, the area of the capital more than doubled, going from 1,091 to 2,511 square kilometers, resulting in Moscow becoming the largest city on the European continent by area. Moscow is situated on the Moskva River in the Central Federal District of European Russia, making it Europe's most populated inland city; the city is well known for its architecture its historic buildings such as Saint Basil's Cathedral with its colorful architectural style. With over 40 percent of its territory covered by greenery, it is one of the greenest capitals and major cities in Europe and the world, having the largest forest in an urban area within its borders—more than any other major city—even before its expansion in 2012; the city has served as the capital of a progression of states, from the medieval Grand Duchy of Moscow and the subsequent Tsardom of Russia to the Russian Empire to the Soviet Union and the contemporary Russian Federation.
Moscow is a seat of power of the Government of Russia, being the site of the Moscow Kremlin, a medieval city-fortress, today the residence for work of the President of Russia. The Moscow Kremlin and Red Square are one of several World Heritage Sites in the city. Both chambers of the Russian parliament sit in the city. Moscow is considered the center of Russian culture, having served as the home of Russian artists and sports figures and because of the presence of museums and political institutions and theatres; the city is served by a transit network, which includes four international airports, nine railway terminals, numerous trams, a monorail system and one of the deepest underground rapid transit systems in the world, the Moscow Metro, the fourth-largest in the world and largest outside Asia in terms of passenger numbers, the busiest in Europe. It is recognized as one of the city's landmarks due to the rich architecture of its 200 stations. Moscow has acquired a number of epithets, most referring to its size and preeminent status within the nation: The Third Rome, the Whitestone One, the First Throne, the Forty Soroks.
Moscow is one of the twelve Hero Cities. The demonym for a Moscow resident is "москвич" for male or "москвичка" for female, rendered in English as Muscovite; the name "Moscow" is abbreviated "MSK". The name of the city is thought to be derived from the name of the Moskva River. There have been proposed several theories of the origin of the name of the river. Finno-Ugric Merya and Muroma people, who were among the several Early Eastern Slavic tribes which inhabited the area, called the river Mustajoki, it has been suggested. The most linguistically well grounded and accepted is from the Proto-Balto-Slavic root *mŭzg-/muzg- from the Proto-Indo-European *meu- "wet", so the name Moskva might signify a river at a wetland or a marsh, its cognates include Russian: музга, muzga "pool, puddle", Lithuanian: mazgoti and Latvian: mazgāt "to wash", Sanskrit: májjati "to drown", Latin: mergō "to dip, immerse". In many Slavic countries Moskov is a surname, most common in Bulgaria, Russia and North Macedonia. There exist as well similar place names in Poland like Mozgawa.
The original Old Russian form of the name is reconstructed as *Москы, *Mosky, hence it was one of a few Slavic ū-stem nouns. As with other nouns of that declension, it had been undergoing a morphological transformation at the early stage of the development of the language, as a result the first written mentions in the 12th century were Московь, Moskovĭ, Москви, Moskvi, Москвe/Москвѣ, Moskve/Moskvě. From the latter forms came the modern Russian name Москва, a result of morphological generalisation with the numerous Slavic ā-stem nouns. However, the form Moskovĭ has left some traces in many other languages, such as English: Moscow, German: Moskau, French: Moscou, Georgian: მოსკოვი, Latvian: Maskava, Ottoman Turkish: Moskov, Tatar: Мәскәү, Mäskäw, Kazakh: Мәскеу, Mäskew, Chuvash: Мускав, etc. In a similar manner the Latin name Moscovia has been formed it became a collo
Rally is a form of motorsport that takes place on public or private roads with modified production or specially built road-legal cars. It is distinguished by running not on a circuit, but instead in a point-to-point format in which participants and their co-drivers drive between set control points, leaving at regular intervals from one or more start points. Rallies may be won by pure speed within the stages or alternatively by driving to a predetermined ideal journey time within the stages; the term "rally", as a branch of motorsport dates from the first Monte Carlo Rally of January 1911. Until the late 1920s, few if any other events used the term. Rallying itself can be traced back to the 1894 Paris–Rouen Horseless Carriage Competition, sponsored by a Paris newspaper, Le Petit Journal, which attracted considerable public interest and entries from leading manufacturers. Prizes were awarded to the vehicles by a jury based on the reports of the observers who rode in each car; this event led directly to a period of city-to-city road races in France and other European countries, which introduced many of the features found in rallies: individual start times with cars running against the clock rather than head to head.
The first of these great races was the Paris–Bordeaux–Paris race of June 1895, won by Paul Koechlin in a Peugeot, despite arriving 11 hours after Émile Levassor in a Panhard et Levassor. Levassor's time for the 1,178 km course, running without a break, was 48 hours and 48 minutes, an average speed of 24 km/h. From 24 September-3 October 1895, the Automobile Club de France sponsored the longest race to date, a 1,710 km event, from Bordeaux to Agen and back; because it was held in ten stages, it can be considered the first rally. The first three places were taken by a Panhard, a Panhard, a three-wheeler De Dion-Bouton. In the Paris–Madrid race of May 1903, the Mors of Fernand Gabriel took just under five and a quarter hours for the 550 km to Bordeaux, an average of 105 km/h. Speeds had now far outstripped the safe limits of dusty highways thronged with spectators and open to other traffic and animals; the French government banned this style of event. From on, racing in Europe would be on closed circuits on long loops of public highway and in 1907, on the first purpose-built track, England's Brooklands.
Racing was going its own separate way. One of the earliest of road races, the Tour de France of 1899, was to have a long history, running 18 times as a reliability trial between 1906 and 1937, before being revived in 1951 by the Automobile Club de Nice. Italy had been running road competitions since 1895, when a reliability trial was run from Turin to Asti and back; the country's first true motor race was held in 1897 along the shore of Lake Maggiore, from Arona to Stresa and back. This led to a long tradition of road racing, including events like Sicily's Targa Florio and Giro di Sicilia, which went right round the island, both of which continued on and off until after World War II; the first Alpine event was held in 1898, the Austrian Touring Club's three-day Automobile Run through South Tyrol, which included the infamous Stelvio Pass. In Britain, the legal maximum speed of 12 mph precluded road racing, but in April and May 1900, the Automobile Club of Great Britain organised the Thousand Mile Trial, a 15-day event linking Britain's major cities, in order to promote this novel form of transport.
Seventy vehicles took part, the majority of them trade entries. They had to complete thirteen stages of route varying in length from 43 to 123 miles at average speeds of up to the legal limit of 12 mph, tackle six hillclimb or speed tests. On rest days and at lunch halts, the cars were shown to the public in exhibition halls; this was followed in 1901 by a five-day trial based in Glasgow The Scottish Automobile Club organised an annual Glasgow–London non-stop trial from 1902 to 1904 the Scottish Reliability Trial from 1905. The Motor Cycling Club allowed cars to enter its trials and runs from 1904. In 1908 the Royal Automobile Club held its 2,000 mi International Touring Car Trial, 1914 the important Light Car Trial for manufacturers of cars up to 1400 cc, to test comparative performances and improve the breed. In 1924, the exercise was repeated as the Small Car Trials. In Germany, the Herkomer Trophy was first held in 1905, again in 1906; this challenging five-day event attracted over 100 entrants to tackle its 1,000 km road section, a hillclimb and a speed trial, but sadly it was marred by poor organisation and confusing regulations.
One participant had been Prince Henry of Austria, inspired to do better, so he enlisted the aid of the Imperial Automobile Club of Germany to create the first Prinz Heinrich Fahrt in 1908. Another trial was held in 1910; these were successful, attracting top drivers and works cars from major teams – several manufacturers added "Prince Henry" models to their ranges. The first Alpine Trial was held in 1909, in Aus
Saint Petersburg is Russia's second-largest city after Moscow, with 5 million inhabitants in 2012, part of the Saint Petersburg agglomeration with a population of 6.2 million. An important Russian port on the Baltic Sea, it has a status of a federal subject. Situated on the Neva River, at the head of the Gulf of Finland on the Baltic Sea, it was founded by Tsar Peter the Great on 27 May 1703. During the periods 1713–1728 and 1732–1918, Saint Petersburg was the capital of Imperial Russia. In 1918, the central government bodies moved to Moscow, about 625 km to the south-east. Saint Petersburg is one of the most modern cities of Russia, as well as its cultural capital; the Historic Centre of Saint Petersburg and Related Groups of Monuments constitute a UNESCO World Heritage Site. Saint Petersburg is home to the Hermitage, one of the largest art museums in the world. Many foreign consulates, international corporations and businesses have offices in Saint Petersburg. An admirer of everything German, Peter the Great named the city, Sankt-Peterburg.
On 1 September 1914, after the outbreak of World War I, the Imperial government renamed the city Petrograd, meaning "Peter's city", in order to expunge the German name Sankt and Burg. On 26 January 1924, shortly after the death of Vladimir Lenin, it was renamed to Leningrad, meaning "Lenin's City". On 6 September 1991, Sankt-Peterburg, was returned. Today, in English the city is known as "Saint Petersburg". Local residents refer to the city by its shortened nickname, Piter; the city's traditional nicknames among Russians are the Window to Europe. Swedish colonists built Nyenskans, a fortress at the mouth of the Neva River in 1611, in what was called Ingermanland, inhabited by Finnic tribe of Ingrians; the small town of Nyen grew up around it. At the end of the 17th century, Peter the Great, interested in seafaring and maritime affairs, wanted Russia to gain a seaport in order to trade with the rest of Europe, he needed a better seaport than the country's main one at the time, on the White Sea in the far north and closed to shipping during the winter.
On 12 May 1703, during the Great Northern War, Peter the Great captured Nyenskans and soon replaced the fortress. On 27 May 1703, closer to the estuary 5 km inland from the gulf), on Zayachy Island, he laid down the Peter and Paul Fortress, which became the first brick and stone building of the new city; the city was built by conscripted peasants from all over Russia. Tens of thousands of serfs died building the city; the city became the centre of the Saint Petersburg Governorate. Peter moved the capital from Moscow to Saint Petersburg in 1712, 9 years before the Treaty of Nystad of 1721 ended the war. During its first few years, the city developed around Trinity Square on the right bank of the Neva, near the Peter and Paul Fortress. However, Saint Petersburg soon started to be built out according to a plan. By 1716 the Swiss Italian Domenico Trezzini had elaborated a project whereby the city centre would be located on Vasilyevsky Island and shaped by a rectangular grid of canals; the project is evident in the layout of the streets.
In 1716, Peter the Great appointed Frenchman Jean-Baptiste Alexandre Le Blond as the chief architect of Saint Petersburg. The style of Petrine Baroque, developed by Trezzini and other architects and exemplified by such buildings as the Menshikov Palace, Kunstkamera and Paul Cathedral, Twelve Collegia, became prominent in the city architecture of the early 18th century. In 1724 the Academy of Sciences and Academic Gymnasium were established in Saint Petersburg by Peter the Great. In 1725, Peter died at the age of fifty-two, his endeavours to modernize Russia had met with opposition from the Russian nobility—resulting in several attempts on his life and a treason case involving his son. In 1728, Peter II of Russia moved his seat back to Moscow, but four years in 1732, under Empress Anna of Russia, Saint Petersburg was again designated as the capital of the Russian Empire. It remained the seat of the Romanov dynasty and the Imperial Court of the Russian Tsars, as well as the seat of the Russian government, for another 186 years until the communist revolution of 1917.
In 1736–1737 the city suffered from catastrophic fires. To rebuild the damaged boroughs, a committee under Burkhard Christoph von Münnich commissioned a new plan in 1737; the city was divided into five boroughs, the city centre was moved to the Admiralty borough, situated on the east bank between the Neva and Fontanka. It developed along three radial streets, which meet at the Admiralty building and are now one street known as Nevsky Prospekt, Gorokhovaya Street and Voznesensky Prospekt. Baroque architecture became dominant in the city during the first sixty years, culminating in the Elizabethan Baroque, represented most notably by Italian Bartolomeo Rastrelli with such buildings as the Winter Palace. In the 1760s, Baroque architecture was succeeded by neoclassical architecture. Established in 1762, the Commission of Stone Buildings of Moscow and Saint Petersburg ruled that no structure in the
Gold is a chemical element with symbol Au and atomic number 79, making it one of the higher atomic number elements that occur naturally. In its purest form, it is a bright reddish yellow, soft and ductile metal. Chemically, gold is a group 11 element, it is solid under standard conditions. Gold occurs in free elemental form, as nuggets or grains, in rocks, in veins, in alluvial deposits, it occurs in a solid solution series with the native element silver and naturally alloyed with copper and palladium. Less it occurs in minerals as gold compounds with tellurium. Gold is resistant to most acids, though it does dissolve in aqua regia, a mixture of nitric acid and hydrochloric acid, which forms a soluble tetrachloroaurate anion. Gold is insoluble in nitric acid, which dissolves silver and base metals, a property that has long been used to refine gold and to confirm the presence of gold in metallic objects, giving rise to the term acid test. Gold dissolves in alkaline solutions of cyanide, which are used in mining and electroplating.
Gold dissolves in mercury, forming amalgam alloys. A rare element, gold is a precious metal, used for coinage and other arts throughout recorded history. In the past, a gold standard was implemented as a monetary policy, but gold coins ceased to be minted as a circulating currency in the 1930s, the world gold standard was abandoned for a fiat currency system after 1971. A total of 186,700 tonnes of gold exists above ground, as of 2015; the world consumption of new gold produced is about 50% in jewelry, 40% in investments, 10% in industry. Gold's high malleability, resistance to corrosion and most other chemical reactions, conductivity of electricity have led to its continued use in corrosion resistant electrical connectors in all types of computerized devices. Gold is used in infrared shielding, colored-glass production, gold leafing, tooth restoration. Certain gold salts are still used as anti-inflammatories in medicine; as of 2017, the world's largest gold producer by far was China with 440 tonnes per year.
Gold is the most malleable of all metals. It can be drawn into a monoatomic wire, stretched about twice before it breaks; such nanowires distort via formation and migration of dislocations and crystal twins without noticeable hardening. A single gram of gold can be beaten into a sheet of 1 square meter, an avoirdupois ounce into 300 square feet. Gold leaf can be beaten thin enough to become semi-transparent; the transmitted light appears greenish blue, because gold reflects yellow and red. Such semi-transparent sheets strongly reflect infrared light, making them useful as infrared shields in visors of heat-resistant suits, in sun-visors for spacesuits. Gold is a good conductor of electricity. Gold has a density of 19.3 g/cm3 identical to that of tungsten at 19.25 g/cm3. By comparison, the density of lead is 11.34 g/cm3, that of the densest element, osmium, is 22.588±0.015 g/cm3. Whereas most metals are gray or silvery white, gold is reddish-yellow; this color is determined by the frequency of plasma oscillations among the metal's valence electrons, in the ultraviolet range for most metals but in the visible range for gold due to relativistic effects affecting the orbitals around gold atoms.
Similar effects impart a golden hue to metallic caesium. Common colored gold alloys include the distinctive eighteen-karat rose gold created by the addition of copper. Alloys containing palladium or nickel are important in commercial jewelry as these produce white gold alloys. Fourteen-karat gold-copper alloy is nearly identical in color to certain bronze alloys, both may be used to produce police and other badges. White gold alloys can be made with nickel. Fourteen- and eighteen-karat gold alloys with silver alone appear greenish-yellow and are referred to as green gold. Blue gold can be made by alloying with iron, purple gold can be made by alloying with aluminium. Less addition of manganese, aluminium and other elements can produce more unusual colors of gold for various applications. Colloidal gold, used by electron-microscopists, is red. Gold has only one stable isotope, 197Au, its only occurring isotope, so gold is both a mononuclidic and monoisotopic element. Thirty-six radioisotopes have been synthesized, ranging in atomic mass from 169 to 205.
The most stable of these is 195Au with a half-life of 186.1 days. The least stable is 171Au. Most of gold's radioisotopes with atomic masses below 197 decay by some combination of proton emission, α decay, β+ decay; the exceptions are 195Au, which decays by electron capture, 196Au, which decays most by electron capture with a minor β− decay path. All of gold's radioisotopes with atomic masses above 197 decay by β− decay. At least 32 nuclear isomers have been characterized, ranging in atomic mass from 170 to 200. Within that range, only 178Au, 180Au, 181Au, 182Au, 188Au do not have isomers. Gold's most stable isomer is 198m2Au with a half-life of 2.27 days. Gold's least stable isomer is 177m2Au with a half-life of only 7 ns. 184m1Au has three decay paths: β+ decay, isomeric