This is a map of the Petersburg subway, by Alexei Goncharov, showing the depth (in meters) and construction type (“single-vault,” etc.) of each station. The deepest station is Admiralteyskaya, at 86 meters, in downtown Petersburg. The station, which opened in 2011, has a troubled history. For many years, it was a “ghost” station, briefly glimpsed during the long dark transit from Sadovaya to Sportivnaya. Image courtesy of Natalia Yuda and St. Petersburg Photo Diary.