The situation in the Ukrainian peninsula of Crimea escalated Thursday, when pro-Russian gunmen seized the parliament building and raised a Russian flag. The wider region surrounding the Black Sea, known for its idyllic summer resort towns 鈥� including the Olympic city of Sochi 鈥� has been volatile for generations.

Here is a snapshot of some of the current tensions in the region, in the context of the ongoing crisis in Ukraine.

Crimea

The peninsula in southern Ukraine is an autonomous region with its own parliament, although the Ukrainian government has ultimate authority there. Ethnic Russians make up about 60 per cent of the population and the region is strongly pro-Russia.

Crimea was annexed by the Russian empire in the late 18th century. In 1954, when Ukraine was part of the Soviet Union, Soviet leader Nikita Khrushchev signed over Crimea to Ukraine. Things became complicated after communism fell in Eastern Europe and Ukraine was no longer ruled by Moscow.

There have also been clashes between Crimean Tatars and pro-Russian supporters in the region.

Russian military port

Russia has a large military port in the Ukrainian city of Sevastopol, located at the southern tip of Crimea. After the collapse of the Soviet Union, Ukraine began leasing the port to Russia. Russia鈥檚 military presence in Crimea is now a source of concern as pro-Russian gunmen have seized the Crimean parliament. 

South Ossetia

The region of South Ossetia in Russia has long been a location of tension and conflicts. Ethnic Ossetians and Georgians fought in the early 1990s, after South Ossetia said it wanted to secede from Georgia. In 2008, Russia and the former Soviet republic Georgia engaged in a brief war, after which South Ossetia declared its independence. The declaration remains unrecognized by most of the world, with the exception of Russia. The nearby region of Abkhazia is also a breakaway republic.

U.S./NATO presence

Over the years, NATO exercises have taken place on the western side of the Black Sea, off the Bulgarian and Romanian coasts. Last October, construction began on a U.S. base in Romania that is expected to be part of the ballistic missile defence system in Europe. U.S. forces have also been training at Bulgarian bases.