The unrest in Ukraine has now shifted eastward to Crimea. The region is an autonomous part of Ukraine, but with strong emotional ties to Russia and a majority of people who identify themselves as Russian.
Here is why Crimea is important to both Russia and Ukraine.
Location: The Crimean Peninsula juts into the Black Sea, narrowly attached to the Ukrainian mainland. In the east, it almost touches Russia.
But, says Padraic Kenney, a professor at the Indiana University School of Global and International Studies, Crimea has a special place for Russians.
"Traditionally, it's been a place for summer vacations, health visits; 19th-century Russian literature is full of scenes set in Crimea; it was a place for intellectuals to go," he says. "When Russians think of an imaginary map of Russian space, Crimea is part of that map."
Crimea is also of strategic importance to Russia: It's the location of Sevastopol, home to the Russian and previously the Soviet Black Sea naval fleet. In 2010, Russia and Ukraine signed a treaty that would extend Russian naval presence in the city until 2042 (it was previously due to expire in 2017).
History: In a story last year, NPR's Corey Flintoff described the Crimean Peninsula this way:
"Over the centuries, it's been part of the Russian Empire, the Soviet Union and now Ukraine, but before that, it belonged to the Crimean Tatars, descendants of the golden horde of Genghis Khan."
Those historical reasons are part of why Crimea has such an important role in the present conflict in Ukraine.
The important 20th century date in Crimea's history is 1954. That's when Soviet leader Nikita Khrushchev gave the peninsula as a gift to Ukraine. At the time, neither he nor anyone else foresaw the USSR's collapse. After the Soviet Union's demise in 1991, Crimea became part of Ukraine, and remains so to this day but as an autonomous part of the country.
Back in 1945, Crimea was where President Franklin D. Roosevelt, British Prime Minister Winston Churchill and Soviet leader Joseph Stalin met to decide how Europe would be divided after World War II.
Just a year earlier, the peninsula was the scene of a policy decision that has repercussions to this day.
In 1944, Crimea's entire population of ethnic Tatars was rounded up on Stalin's orders and sent to the deserts of what was then Soviet Central Asia. Stalin accused them of collaborating with Germany, who had occupied the peninsula during World War II. The Tatars weren't allowed to return until the late 1980s.
Rewind a little more, and the Crimean Peninsula was the setting for the 1853-56 Crimean War that pitted Russia against an alliance of Britain, France and the Ottoman Empire (for the record, Russia lost). The war was famous for many things: Florence Nightingale, and The Charge of the Light Brigade among them, but it was also the world's first media war.
Reporters and photographers not only covered the fighting, but their dispatches were read the same day thanks to the power of the telegraph. (WNYC's Radio Lab has an excellent episode on the authenticity of one of the famous photographs from the Crimean War).
What Now? About 60 percent of the people in Crimea are ethnic Russians and speak Russian and some are loyal to Russia. The rest are Ukrainians and Tatars. Many Russians in Crimea are opposed to the new government in Kiev, while the Ukrainians and Tatars are believed to be behind the new regime. The two sides are facing off against each other, leading to fears that Crimea may secede and become the next flashpoint in the conflict in Ukraine.
That almost happened in 1994, when Crimea briefly flirted with independence and union with Russia. Andranik Migranyan, a political scientist and director of the Institute for Democracy and Cooperation in New York, a group that has close ties to Russia's leadership, says if that happens again the reaction from Russia might be very different.
Russia, he told NPR's Robert Siegel, views what's happening in Ukraine and Crimea as an "existential crisis." He added:
"I think if there [is] going to be attack against Crimea, an attempt to come there and to seize the power, I think if Crimean-armed people are going to fight, then this could change radically a situation because I'm not sure that the (naval) fleet over there would stay out of this conflict."
Indeed, Russia has accused Ukraine's new government of infringing on the rights of ethnic Russians.
As Mark Memmott reported over on our Two-Way blog, the Ukrainian parliament has inflamed tensions with ethnic Russians by "repealing a law that made Russian a second official language in areas of the nation where the Russian population is greater than 10 percent."
Paul Sonne, a reporter for The Wall Street Journal, who is in the region, told NPR's Melissa Block, that ethnic Russians, fearful of their place in the new Ukraine, are signing up for militias. Here's what he said was happening in Simferopol, the capital of Crimea:
"There were hundreds, probably more than a thousand as some point, maybe 1,500 people there, and you know, from what I can tell, these militias aren't really doing anything yet, but it's sort of this idea that if the [Ukrainian] nationalists come and try to pull down our statues of Lenin or cause havoc here or make us do something that we don't want, we're going to mobilize.
"So in some way it's a show of teeth."
They weren't the only ones: Russian President Vladimir Putin ordered an urgent drill to test the readiness of his armed forces. Dmitri Trenin, the director of the Moscow Carnegie Center, told The New York Times that it's flag waving, but also "a message to Kiev not to impose its rule in Crimea by force."