Königsberg - from Prussian city to forbidden zone

For 700 years Königsberg was the capital of east Prussia, until 1945 when it was destroyed by Allied bombing, followed by the expulsion of the German inhabitants by Stalin and its annexation into Russia. The population in 1939 was given as 372,000.  Stalin then renamed it as Kaliningrad after one of his generals during WW2. It gave Stalin an ice-free port on the Baltic Sea, and 90% of the world's amber resources.

The northern part of east Prussia was also part of the annexation, while the southern part was given to Poland.  Westerners were not allowed into the enclave.

Today things have changed, although being hundreds of kilometres from the rest of Russia through territory that is part of NATO makes things difficult for the inhabitants. Westerners are able to visit it again.

It isn't really a tourist destination though: few people speak anything other than Russian and unlike in Poland, the Russians were not interested in restoring any damaged historic German buildings. Most buildings since 1945 were designed in ugly communist style. Some structures survived WW2, however, such as the old stock exchange (Börse), now a business house.