Kaliningrad, until 1946 known as Königsberg, is the largest city and the administrative centre of Kaliningrad Oblast, the westernmost Oblast of Russia. The city is situated on the Pregolya River, at the head of the Vistula Lagoon on the Baltic Sea, with a population of 489,359 residents, up to 800,000 residents in the urban agglomeration.

The settlement of modern-day Kaliningrad was founded in 1255 on the site of the ancient Old Prussian settlement Twangste by the Teutonic Knights during the Northern Crusades, and was named Königsberg in honor of King Ottokar II of Bohemia. A Baltic port city, it successively became the capital of the State of the Teutonic Order, the Duchy of Prussia (1525–1701) and East Prussia. Königsberg remained the coronation city of the Prussian monarchy, though the capital was moved to Berlin in 1701. From 1454 to 1455 the city under the name of Królewiec belonged to the Kingdom of Poland, and from 1466 to 1657 it was a Polish fief. Königsberg was the easternmost large city in Germany until World War II. The city was heavily damaged by Allied bombing in 1944 and during the Battle of Königsberg in 1945; it was then captured by the Soviet Union on 9 April 1945. The Potsdam Agreement of 1945 placed it under Soviet administration. The city was renamed to Kaliningrad in 1946 in honor of Soviet leader Mikhail Kalinin.

More Info: en.wikipedia.org