Welcome to Kaliningrad
After Kaliningrad Cathedral, the most visible remains of Königsberg are its red-brick fortification walls, bastions and gates, built between the 17th and 19th centuries. The remains of the city's castle were destroyed and replaced by the hideous Dom Sovietov (House of Soviets) in the 1960s. During the eyesore’s construction it was discovered that the land below was hollow, housing a (now-flooded) four-level underground passage connecting to the cathedral. The decaying, half-finished building has never been used.