Odes′sa, the fourth city in Russia, a seaport of the Black Sea, about half way between the Dnieper and Dniester Rivers. It is built facing the sea, on cliffs, with deep ravines, and with galleries hollowed out of the soft rock, in which many of the poorest people live. It is a modern city, founded in 1794 near an old Turkish fort, but has grown rapidly, being the chief shipping-port for the corn-growing districts of southern Russia. The harbor is protected by moles against the dangerous winds of the Black Sea, and is menaced by ice hardly more than a fortnight in the whole year. The trade is largely in grain, principally wheat, but sugar, wool and flour are also exported. It also has sugar and oil refineries, and tobacco, leather, soap and chemicals are manufactured. It has a university with 1,714 students, a public library, historical museum, cathedral, opera-house and great grain warehouses and elevators. Water is brought to the city from the Dniester by an aqueduct 27 miles long. Odessa is known as a home of the cholera, for its persecution of the Jews and as headquarters of the nihilists. Population 520,000.