Tallinn, Ger. Reval, city (1994 pop. 442,679), capital of Estonia, on the Gulf of Finland, opposite Helsinki. It is a major Baltic port, a rail and highway junction, and an industrial center. Tallinn also has military and naval installations. Industries include shipbuilding, metalworking, food and fish processing, and the manufacture of machinery and electrical consumer goods. Tourism is also important. The population is about 55% Estonian and about 40% Russian and Ukrainian. Tallinn contains the Estonian Academy of Sciences, the Estonian National Museum of Art, and many other educational and cultural institutions.

Tallinn was first mentioned by the Arab geographer Idrisi in 1154. It was destroyed in 1219 by Waldemar II of Denmark, who built a fortress there. The city's name comes from the Estonian Taani linn ("Danish castle"). A member of the Hanseatic League from 1285, Tallinn was sold (1346) with the rest of Estonia by Waldemar IV to the Livonian Brothers of the Sword . Upon the dissolution of the Livonian Order in 1561, it passed to Sweden. Captured by Peter I in 1710 during the Northern War, Tallinn was ceded to Russia by the Treaty of Nystad in 1721. It underwent development as a port for Russia's Baltic fleet and in 1870 was linked by rail with St. Petersburg. Tallinn became the capital of independent Estonia in 1919 and of the Estonian SSR in 1940. It suffered considerable damage during the German occupation in World War II. In 1991, it again became the capital of an independent Estonia.

The historical center of Tallinn consists of an upper town, on a steep hill topped by a medieval cathedral, and an adjoining lower town dating from Hanseatic times. The picturesque lower town is surrounded by a medieval wall with massive round towers. Its landmarks include the 13th-century Danish Toompea Castle (rebuilt in 1935 as a government building), the 13th-century Gothic Church of St. Olai, and the 14th-century city hall.