Skrunda-2 is an abandoned Soviet military town which hosted ~5000 inhabitants. It is one of the most easily accessible abandoned towns in the world.
During the Cold War Skrunda-2 it served a radar base to track Western space communication and possible nuclear missile launches.
While the radars themselves have been destroyed as Russian soldiers retreated in 1998, the former residential buildings, school, water tower, officer’s Club and other installations remain.
Skrunda-2 initially after closure used to be guarded. Later it became unguarded and, even though technically prohibited to enter, it attracted increasing amount of tourists, up to ~50-100 people at any given time every summer weekend. Currently (since 2016) it is officially legal to enter, but a fee must be paid at entrance.
What makes Skrunda-2 especially appealing is the fact that all the doors are left open, allowing full exploration (including basements, roofs, etc.). While anything of value has been removed (e.g. metal radiators), many small mementos of the life that used to go on there remain (e.g. somebody’s collection of bubble gum stickers). While the town was within Latvia it was mainly Russian, as evidenced in Russian-only inscriptions and newspapers.
It is advisable to walk carefully as there may be some open shafts.