Russian armed forces effectively seized control of Ukraine's Crimean peninsula on Saturday.
SIMFEROPOL
Scores of heavily armed soldiers tightened their grip on the Crimean capital, Simferopol, surrounding government buildings, shuttering the airport, and blocking streets.
SEVASTOPOL
Russia's Black Sea Fleet is set to be based in Sevastopol until at least 2042, based on an accord between Russia and Ukraine.
Gas pipelines
About 80 percent of Russian gas exports to Europe pass through Ukraine. Europe, in turn, depends on Russia for 40 percent of its imported fuel.
According to Mikhail Korchemkin, head of East European Gas Analysis, a consulting firm in Pennsylvania, the most important pipelines that run through Ukraine are the ones leading to Slovakia. They will eventually take gas to Germany, Austria and Italy.