Crimea is at the crux of negotiations between Russia and Ukraine. Here's why it's important.

Washington-brokered negotiations to end Russia’s war in Ukraine have largely boiled down to a diamond-shaped peninsula about the size of Massachusetts. Crimea had been contested for centuries by the Greeks, Mongols and Ottomans before Russia illegally annexed it from Ukraine in 2014. Sitting at a geographic crossroads between Europe, Asia and the Middle East, the peninsula has vast trade and military significance — and is steeped in spiritual lore.