In 2016, two years after Russia seized Crimea from Ukraine, a black granite memorial was raised in Sailors' Square of the Black Sea city of Yevpatoria with a command to future generations: "We returned Crimea, it's up to you to return Alaska."

Alaska was purchased from Russia during the Andrew Johnson administration in 1867. War had left the Russians hungry for cash, and they sold Alaska for the equivalent today of 45 cents an acre. "CBS Evening News" co-anchor John Dickerson explains.