Hiiumaa is the second largest island in Estonia and is part of the West Estonian archipelago, in the Baltic Sea. It is 22 km from the Estonian mainland, its largest town is Kärdla. It is located within Hiiu County. Hiiumaa was controlled by the Brothers of the Sword in the early 1200s. During this time it was first settled by Germans; the island was ruled from Denmark Sweden in the 1500s and Russia in the 1700s. It became part of Estonia in 1920 before being incorporated into the Soviet Union till 1991, when Estonia again gained its independence. Hiiumaa is the main island of Hiiu County, called Hiiu maakond in Estonian; the Swedish and German name of the island is Dagden and Dagø in Danish. In modern Finnish, it is called Hiidenmaa Hiisi's Land. In Russian it is known as Khiuma. In Old Gutnish, it was Dagaiþ, from. Hiiumaa emerged from the Baltic Sea 8500 years ago due to isostatic uplift after the retreat of the ice cap. Mesolithic settlements are found on the island's Kõpu Peninsula from about 5500 BC.

These settlements seem to be related to seal hunting and extend into the earliest Neolithic. As Hiiumaa is uplifting the local sea level was 20 m higher than today at this time. For this reason these settlements are located far from the modern coastline; the pottery found at these sites is of the Narva Type and is similar to that found on Saaremaa and the Estonian mainland. A series of stone-cist graves are present on the island from the Late Bronze Age through to the Late Iron Age; the first documented record of the island of Dageida was made by contemporary chroniclers in 1228, when Hiiumaa and the rest of Estonia were conquered by Germanic crusaders. In 1254, Hiiumaa was divided between the Bishopric of Ösel-Wiek and the Livonian branch of the Teutonic Order, acting on behalf of the Hanseatic League; the island was part of Swedish Estonia from 1563 to 1721, after which it passed to the Russian Empire as part of the Governorate of Estonia, though Dagö's Swedish population kept most of their privileges.

Most of the island's numerous Swedish-speaking population emigrated or were "Estonianised" during the period of Imperial Russian rule, although a minority remains to this day. Estonian Swedes are known as "aibofolke" or "rannarootslased". Hiiumaa was occupied during World War I in Operation Albion. After the war, it became a part of independent Estonia; the waters near Hiiumaa were active during World War II: 23 June 1941- The Soviet destroyer Gnevny was sunk by a German seamine. 25 June- the Soviet minesweeper T-208 Shkiv was destroyed by a German seamine. 27 June- Two German motor torpedo boats, S43 and S106, were destroyed by Soviet seamines. 1 July- the Soviet submarine M-81 was destroyed by a German seamine north of Hiiumaa. 7 July- the Soviet minesweeper T-216 was sunk. 30 July- the Soviet minesweeper T-201 Zarjad was sunk. 10 August- the German submarine U-144 was sunk by a torpedo from the Soviet submarine SC-307. Hiiumaa Island was annexed by the Soviet Union in 1940, by Nazi Germany in 1941, by the Soviets again in 1944.

It was part of the Estonian Soviet Socialist Republic until the Soviet Union collapsed in 1991. During the Soviet era, Hiiumaa was declared a restricted zone, closed to foreigners and to most mainland Estonians. Since 1991, the island has been a part of independent Estonia. A number of derelict Soviet era forts and communication towers are still present on the islands northern coast. Hiiumaa is an island in Estonia located north of Saaremaa in the Baltic Sea, it is the northernmost island in the Muhu archipelago, which includes Muhu. Hiiumaa has a low relief and is formed of limestone, exposed in cliffs around parts of the islands coast. In the North of the island there are a series of fossilized beaches preserved as uplift has occurred; the modern beaches are on the northern and western coast lines. The natural environment is protected within the Tahkuna Nature Reserve and West Estonian Archipelago Biosphere Reserve; the Hiiu Shoal is located off the northwestern shore of Hiiumaa Island. The Soela Strait separates Hiiumaa from Saaremaa to its south, the Muhu Strait separates it from the mainland of Estonia.

The fauna and flora of Hiiumaa is similar to the Estonian mainland. The mammal fauna includes elk, red deer, roe deer, wild boars, foxes and martens. Wolves have started to repopulate the island after being made locally extinct. Minks were reintroduced in 2000, after they were exterminated by trappers. Since the end of the 1990s the island shelters a conservation project aimed at restoring populations of European mink, an endangered species of which there is about only 1,000 individual specimens left in Europe as of 2017; this project started with removing from the island all American minks that had escaped from breeding farms, reintroducing some European minks. The latter started breeding; the bird species found on the island include black storks, golden eagles, cranes and swans. The forests are dominated by pine and deciduous trees, the rest of the uncultivated land is covered by swamps and dunes; the island has about 1000 species of large plants. The exposed geology of Hiiumaa is composed of Paleozoic Limestone which dips towards the South, covered by glacial sediments.

In the North of the island the limestones are Ordovician and they young upwards to the Silurian in the South. These limesto

Ball-in-a-maze puzzle

Ball-in-a-maze puzzles are dexterity puzzles which involve manipulating either a maze or one or several balls so that the ball or balls are manoeuvered towards a goal. Toys like this have been popular since "Pigs in Clover" was invented by Charles Martin Crandall in the 1880s, with the patent being applied for in 1889. In some versions a wooden labyrinth is tilted using two knobs and the ball has to be navigated past a series of holes and obstacles. A magnet is used in other versions. Perplexus is an example of a 3D ball-in-a-maze. A large number of virtual versions have become available. Another version molded in transparent plastic, uses the ball as a key to opening an internal compartment by manipulating the ball into position, operating a sliding mechanism that releases an access door, they are sometimes called puzzle boxes. Labyrinth Rubik's 360 Perplexus