Crimea is a pro-Russia part of Ukraine separated from the rest of the country geographically, historically and politically. And it's where Ukrainian President Viktor Yanukovych was last reported seen. Here's some key information about it:
ON THE BLACK SEA
The Crimean Peninsula juts into the Black Sea, all but an island except for a narrow strip of land connecting it to the mainland. On its eastern shore, a finger of land reaches out almost to Russia. It's best known in the West as the site of the 1945 Yalta Conference, where Soviet dictator Josef Stalin, President Franklin D. Roosevelt and British Prime Minister Winston Churchill sealed the postwar division of Europe.
WHY IT'S PART OF UKRAINE
Crimea only became part of Ukraine when Soviet leader Nikita Khrushchev gave the peninsula to his native land in 1954. This hardly mattered until the Soviet Union broke up in 1991 and Crimea ended up in an independent Ukraine. Despite that, nearly 60 percent of its population of 2 million identify themselves as Russians.
THE BLACK SEA FLEET
On Crimea's southern shore sits the port city of Sevastopol, home to the Russian Black Sea Fleet and its thousands of naval personnel. Russia kept its half of the Soviet fleet, but was rattled in 2009 when Yanukovych's predecessor warned that it would have to leave the key port by 2017. Shortly after Yanukovych was elected president in 2010, he agreed to extend the Russian lease until 2042.
The 1991 fall of the Soviet Union also brought the return of the Crimean Tatars, who had been brutally deported in 1944 under Stalin. The Crimean Tatars, who now make up about 12 percent of its population, have sided with the anti-Yanukovych protesters in Kiev who drove his government from power.
British nurse Florence Nightingale was celebrated for treating wounded soldiers during the Crimean War of the mid-19th century, which Russia lost to an alliance that included Britain, France and the Ottoman Empire. She is now considered the founder of modern nursing.