In 1890, fearful of the threat from German naval power, the Tsarist authorities began construction of a planned military suburb four kilometres north of central Liepaja. Called the Port of Alexander III, it was a fully autonomous community with its own electricity power plant, sewage system, cathedral and schools and was home to Russia's Baltic fleet. A line of fortifications was built to protect the port from attack and a swing bridge, based on drawings made by Gustav Eiffel, was constructed to link the suburb with Liepaja.
Abandoned at the outbreak of WW1, when blockships were sunk at the port entrance, the area was taken over by the independent Latvian state and was renamed Karosta, a contraction of kara osta, or naval port. During the Soviet Occupation it housed a submarine fleet and was off-limits to foreigners. When the Soviet military finally left in 1994 the Russian civilian population stayed behind. Nowadays Karosta is showing its age. Bleak and dilapidated, it's an open-air museum to the end of monarchy and fifty years of totalitarian rule.
Bus numbers 3,7 or 8 run from central Liepaja to General Baloza iela, passing a red-brick tower built in 1905 to provide drinking water to the military population. At the junction with Pulkveza Brieza iela you'll see the unmistakeable gold onion domes of St Nicholas Orthodox Maritime Cathedral towering above wasteground and empty-shell apartment blocks. One of the largest Orthodox churches in Latvia, it's consecration was attended by Tsar Nicholas himself. Used for Lutheran services during the inter-war Latvian republic, the Soviets turned it into a cinema and sports hall, bricking up the cupola in the process. In 1994 it was re-consecrated and is now used for Orthodox services.
A few minutes walk away is Karosta Cietums, the only military prison in Europe to be open to visitors. Guided tours can be booked year round and are highly recommended. The same organisation runs torchlit tours of the labyrinth of tunnels that make up the North Forts at the far end of the suburb.
The area around the cathedral is run-down, decaying grey apartment buildings with gaping holes where windows once were, and red-brick ruins of old naval buildings. The remaining population is mostly Russian, civilians left high and dry when the Soviet military were forced to leave and the Latvian navy decamped to the city centre three years later. Take away the big cars and you could be back in the 1980s, old women chatting on bus stop benches and men wandering dead-eyed and aimlessly with beer and empty shopping bags.
Whatever else you do in Liepaja, Karosta's a place you really shouldn't miss.