Underwater archaeology is archaeology practiced underwater. As with all other branches of archaeology, it evolved from its roots in pre-history and in the classical era to include sites from the historical and industrial eras, its acceptance has been a late development due to the difficulties of accessing and working underwater sites, because the application of archaeology to underwater sites emerged from the skills and tools developed by shipwreck salvagers. As a result, underwater archaeology struggled to establish itself as bona fide archaeological research; the situation changed when universities began teaching the subject and when a theoretical and practical base for the sub-discipline was established. Underwater archaeology now has a number of branches including, after it became broadly accepted in the late 1980s, maritime archaeology: the scientifically based study of past human life and cultures and their activities in, on, around and under the sea and rivers; this is most effected using the physical remains found in, around or under salt or fresh water or buried beneath water-logged sediment.

In recent years, the study of submerged WWII sites and of submerged aircraft in the form of underwater aviation archaeology have emerged as bona fide activity. Though mistaken as such, underwater archaeology is not restricted to the study of shipwrecks. Changes in sea level because of local seismic events such as the earthquakes that devastated Port Royal and Alexandria or more widespread climatic changes on a continental scale mean that some sites of human occupation that were once on dry land are now submerged. At the end of the last ice age, the North Sea was a great plain, anthropological material, as well as the remains of animals such as mammoths, are sometimes recovered by trawlers; because human societies have always made use of water, sometimes the remains of structures that these societies built underwater still exist when traces on dry land have been lost. As a result, underwater archaeological sites cover a vast range including: submerged indigenous sites and places where people once lived or visited that have been subsequently covered by water due to rising sea levels.

Underwater archaeology is complementary to archaeological research on terrestrial sites because the two are linked by many and various elements including geographic, political and other considerations. As a result, a study of an archaeological landscape can involve a multidisciplinary approach requiring the inclusion of many specialists from a variety of disciplines including prehistory, historical archaeology, maritime archaeology, anthropology. There are many examples. One is the wreck of the VOC ship Zuytdorp lost in 1711 on the coast of Western Australia, where there remains considerable speculation that some of the crew survived and, after establishing themselves on shore, intermixed with indigenous tribes from the area; the archaeological signature at this site now extends into the interaction between indigenous people and the European pastoralists who entered the area in the mid-19th century. There are many reasons why underwater archaeology can make a significant contribution to our knowledge of the past.

In the shipwreck field alone, individual shipwrecks can be of significant historical importance either because of the magnitude of loss of life or circumstances of loss. Shipwrecks such as Mary Rose can be important for archaeology because they can form a kind of accidental time capsule, preserving an assemblage of human artifacts at the moment in time when the ship was lost. Sometimes it is not the wrecking of the ship, important, but the fact that we have access to the remains of it where the vessel was of major importance and significance in the history of science and engineering, due to being the first of its type of vessel; the development of submarines, for example, can be traced via underwater archaeological research, via the Hunley, the first submarine to sink an enemy ship. All traces of human existence underwater which are one hundred years old or more are protected by the UNESCO Convention on the Protection of the Underwater Cultural Heritage; this convention aims at preventing the destruction or loss of historic and cultural information and looting.

It helps states parties to protect their underwater cultural heritage with an international legal framework. On the basis of the recommendations defined in the above-mentioned UNESCO Convention various European projects have been funded such as the CoMAS project for in situ conservation planning of underwater archaeological artefacts. Underwater sites are difficult to access, more hazardous, compared with working on dry land. In order to access the site directly, diving equipment and diving skills are necessary; the depths that can be accessed by divers, the length of time available at depths, are limited. For deep sites beyond the reach of divers, submarines or remote sensing equipment are needed. For a m

The purple hairstreak is a butterfly in the family Lycaenidae distributed throughout much of Europe, North Africa, Anatolia and Transcaucasia. The larva feeds on Quercus petraea, Quercus cerris and Quercus ilex. N. quercus interjectus Italy N. quercus longicaudatus Armenia, Turkey, West Iran N. quercus iberica Morocco, Iberia Z. quercus L.. Male above with a blue gloss and narrow black distal border, the female with the basal area of the forewing blue and the cell of the hindwing bluish. Underside leaden-grey, with a proximally dark-edged white line before the outer third and in the anal area of the hindwing weak yellow spots. Ab. obsoleta Tutt are females without any blue gloss. Ab. pallescens Tutt are males with a pale grey greenish instead of blue gloss. In ab. excessus Tutt the hindmargin of the forewing bears a coppery streak. Courvoisier proposes the name ab. latefasciata for specimens with broader white line on the underside, ab. bellus Gerh. are females with small orange spots at the apex of the cell of the forewing, which are reduced to two spots in ab. bipunctatus Tutt and to one in ab. unipunctus Tutt.

Distributed, occurring throughout Europe and Asia Minor from England and the Atlantic coast to Armenia and from North Europe to the Mediterranean — Beyond the Mediterranean Sea and on the Iberian Peninsula there occurs iberica Stgr.. Larger, above dark, the blue area of the male sharply defined but not extended. Underside paler silvery grey, the whitish line therefore being less prominent. — Egg semiglobular, whitish grey, granulose. The larva, developed in the sunmier, does not leave the egg before April, it is a dreadful cannibal and is evidently avoided by insect-eating birds, as it has been found unmolested in the nest of the blue tit containing young birds. On the other hand it is much infested with ichneumons, as well as a species of Tachina, which develops after the pupation of the caterpillar. Adult yellowish brown with a reddish tint, on the back a row of triangles connected by a dark line, the sides greenish. On various species of oak, said to occur on other plants; the pupa rounded, irregularly spotted with blackish,on the back three rows of dark spots.

The butterflies occur from June till August everywhere in the plains and hills, but singly, in certain years more plentifully. They rest on the outer twigs of oak-bushes with the wings always closed, but sometimes flutter high up about the crowns of old oaks; this active little butterfly is most seen fluttering around high up in oak trees on warm sunny July and early August days. Males have a glossy purple sheen on the upperside, females have two patches on the forewing only; the underside is light grey with a white streak, edged in black, running down the middle of both wings. The hindwings have a short tail with two orange spots at the base on the underside, it is common and widespread across southern and central England and Wales, becoming rarer and more isolated in the north as far as central Scotland. In Ireland it occurs in a few isolated colonies scattered across the country but is still under recorded due to its reclusive habits. Males tend to stay high up in trees, females come down to lower levels to lay eggs.

Both sexes feed on honeydew although females are attracted to flowers whilst taking a break from egg laying. Eggs are laid singly at the base of oak buds in late summer ready to hatch the following spring as the buds break. Both sessile oak Quercus petraea and pedunculate oak Quercus robur, Britain's two native oaks are used and some introduced species such as Turkey oak Quercus cerris and evergreen oak Quercus ilex. In winter the eggs are found on close examination of bare branches; the caterpillar is developed inside the egg after two or three weeks but doesn't hatch until the spring whereupon it burrows into the flower buds to feed safely concealed. As it gets larger and the buds open it feeds only at night. Pupation takes place in the leaf litter where it is tended by ants who bury them, but sometimes in a crevice in the bark of the foodplant. There is one brood a year with adults on the wing in August. Butterfly Conservation Armenia List of butterflies of Great Britain

3Fun is a location-based mobile online dating application for Android and iOS. It is the most used dating mobile app for polyamorous couples. Catering to people seeking alternative relationships, 3Fun is notable for being the leading dating mobile app for polyamorous couples. 3Fun is used alongside Feeld, Tinder, OkCupid, many other notable mobile dating applications. 3Fun is used in the United States, United Kingdom, other countries. In the Nottingham area of the UK alone, it is used by more than 2,000 people. Other cities where 3Fun is most popular include New York City, San Antonio and Glasgow, Scotland. Outside English-speaking countries, it is used in Brazil, the Netherlands, Spanish-speaking countries, various other countries; the application is popular among Generation Y users. As of May 2019, there were 100,000 monthly downloads, more than 2 million total downloads. Other similar niche dating apps comparable to 3Fun include Feeld. Launched in 2016, 3Fun includes features such as: Photo gesture verification system Privacy protection system Free chat system Synchronous chat system Comparison of online dating services Feeld Grindr Scruff Spoonr Official website Crunchbase profile LinkedIn profile