The Republic of Crimea, a part of Ukraine, lies on a peninsula stretching out from the south of Ukraine between the Black Sea and the Sea of Azov. It is separated from Russia to the east by the narrow Kerch Strait.
The Russian Tsars and Soviet elite spent summers on its subtropical southern shores which still attract holidaymakers and, latterly, wealthy property developers.
Crimea was annexed by the Russian Empire during the reign of Catherine The Great in 1783 and remained part of Russia until 1954 when it was transferred to Ukraine under the then Soviet leader Nikita Khrushchev.
Ethnic Russians still make up the bulk of the population, Ukrainians under a quarter and the Muslim Crimean Tatars about 12%.
For centuries under Greek and Roman influence, Crimea in 1443 became the centre of a Tatar Khanate, which later became an Ottoman vassal state.
Rival imperial ambitions in the mid 19th century led to the Crimean War when Britain and France, suspicious of Russian ambitions in the Balkans as the Ottoman Empire declined, sent troops.
Given autonomous republic status within Russia after the Bolshevik revolution, Crimea was occupied by the Nazis in the early 1940s.Tatar deportation
The Tatars were accused of collaboration by Stalin and deported en masse to Central Asia and Siberia in 1944. Many did not survive.
Only as the Soviet Union collapsed were they allowed to return. By the time over a quarter of a million did so in the early 1990s, it was to an independent Ukraine where they faced very high unemployment and extremely poor housing conditions.
There have been persistent tensions and protests over land rights, and allocation of land to Crimean Tatars remains a highly contentious issue.
After Ukrainian independence, political figures from the local Russian community sought to assert sovereignty and strengthen ties with Russia through a series of moves declared unconstitutional by Kiev.
The 1996 Ukrainian constitution stipulated that Crimea would have autonomous republic status but reasserted that Crimean legislation must be in keeping with that of Ukraine.
Crimea has its own parliament and government with powers over agriculture, public infrastructure and tourism.
The Crimean Tatars have their own unofficial parliament, the Mejlis, which states its purpose as being to promote the rights and interests of the Crimean Tatars.Ukraine-Russia tension
The port of Sevastopol is a major naval base and has been home to the Black Sea Fleet since Soviet times. Following the collapse of the USSR, the fleet was divided up between Russia and Ukraine.
The continuing presence of the Russian fleet in Sevastopol has been a focus of tension between Russia and Ukraine. In 2008, Ukraine - then under the pro-Western President Viktor Yuschenko - demanded that Moscow not use the Black Sea Fleet during the its conflict with Georgia.
Both countries had agreed to allow the Russian fleet to stay until 2017, but after the election of the pro-Russian Viktor Yanukovych as president in 2010, Ukraine agreed to extend the lease by 25 years beyond 2017, in return for cheaper Russian gas.
There was also friction over plans - later scrapped by Mr Yanukovych - by Mr Yushchenko to strengthen ties with Nato. In 2006, ethnic Russians took to the streets to disrupt preparations for Nato-led naval exercises off Crimea.
There is a rumbling border dispute between Moscow and Kiev in the Kerch Strait. Tensions rose sharply in late 2003 after Russia started building a causeway between the Russian coast and the island of Tuzla, just off Crimea.