Russian opposition leader Boris Nemtsov, who was shot dead last Friday, was one of the most outspoken critics of President Vladimir Putin. No arrests have been made in his killing. Ivan Sekretarev/AP hide caption

itoggle caption Ivan Sekretarev/AP

Russian soldiers guard the entrance to the Ukrainian military base in Perevalne, Crimea, last March. Russia was criticized widely internationally after seizing the region. Now Russian lawmakers are considering a bill that says Crimea was illegally given to Ukraine in 1954 and should have been part of Russia all along. Ivan Sekretarev/AP hide caption

itoggle caption Ivan Sekretarev/AP

NPR's Morning Edition host Steve Inskeep interviews President Obama on Dec. 17 in the Oval Office, where they discussed U.S. involvement in the Middle East and the world as a whole. Kainaz Amaria/NPR hide caption

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President Vladimir Putin speaks in Moscow on Dec. 23. Russia's current economic crisis stems from Western sanctions and diving oil prices. Maxim Shipenkov/AFP/Getty Images hide caption

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Russian President Vladimir Putin speaks in front of the map of the Russian Federation, with Crimea on the left of the map, during his annual news conference in Moscow, Russia, on Thursday. The Kremlin has responded angrily to the latest round of U.S.-EU sanctions over the annexation of Crimea. Alexei Druzhinin/AP hide caption

itoggle caption Alexei Druzhinin/AP

Valentin Danilov, 83, is a former executive officer on a Soviet sub who proudly wears his old Soviet military uniform. Crimeans like Danilov have, without changing their residence, lived in three different countries in the past 25 years — the Soviet Union, then Ukraine and now Russia. Max Avdeev for NPR hide caption

itoggle caption Max Avdeev for NPR

Russia established the Crimean port of Sevastopol in the 18th century. After the Soviet breakup in 1991, Russia and Ukraine shared the naval base. But Russia has now taken the entire base, including Ukrainian ships. Max Avdeev for NPR hide caption

itoggle caption Max Avdeev for NPR

A woman removes debris from a cafe that was destroyed during fighting between Ukrainian forces and pro-Russian militants Aug. 5 in the eastern Ukrainian city of Slavyansk, in the region of Donetsk. Anatolii Stepanov/AFP/Getty Images hide caption

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Crimea's new prime minister, Sergei Aksyonov (right), and the speaker of the legislature, Vladimir Konstantinov, attend a rally at Red Square in Moscow on March 18, the day Russia annexed the territory. Russia is pumping billions into Crimea after taking it from Ukraine. However, corruption has been a major problem in Crimea. Pavel Golovkin/AP hide caption

itoggle caption Pavel Golovkin/AP

President Vladimir Putin lays flowers during a ceremony marking Victory Day in the Crimean city of Sevastopol on Friday. It was his first visit to the region since Russia annexed it in March. Maxim Shemetov/Reuters/Landov hide caption

itoggle caption Maxim Shemetov/Reuters/Landov

Communist Party supporters carry red flags during their rally to mark International Labor Day in downtown Kharkiv, Ukraine, on Thursday. In recent weeks, pro-Russia separatists have seized key installations in several cities in eastern Ukraine. Volodymyr Petrov/EPA/Landov hide caption

itoggle caption Volodymyr Petrov/EPA/Landov