China lends money. That's all.
And, how many countries did Russia invade since the dissolution of the USSR?.. How many times did Russia invade (or, attempted to invade) Ukraine since 1991?..
Crimea was part of Russia since 1783, when Catherine the Great put an end to the penisular being a center of slavery trade (yes, by Tatars, who terrorized Russian villages, looting, killing, burning and taking people into slavery.)
Crimea had several referendums and never wanted to be part of Ukraine. Yet, every time, Russia was refusing to accept it. And, only when elected president in Kiev was toppled (with the help of our Canadian Ukrainians) and ultra nationalistic elements were installed as a result of a military coup, Russia agreed to accept Crimea back.
Where else has it expanded since 1991?.. 
Compare that with NATO expansion towards Russian border...