Odesa, Ukraine

Odesa is Ukraine's third-largest city, home to roughly one million residents on the northern shore of the Black Sea. Founded in 1794 by Empress Catherine the Great on the site of a former Ottoman fortress, it developed into a major grain-exporting seaport. The iconic Potemkin Steps, built between 1837 and 1841, descend 142 meters down to the harbor across 192 granite steps designed to create an optical perspective. Beneath the urban grid, the Odesa Catacombs extend across roughly 2,500 kilometers of underground limestone tunnels.