The Moscow Metro is a rapid transit system serving Moscow, Russia and the neighbouring Moscow Oblast cities of Krasnogorsk, Reutov, Lyubertsy and Kotelniki. Opened in 1935 with one 11-kilometre (6.8 mi) line and 13 stations, it was the first underground railway system in the Soviet Union. As of 2018, the Moscow Metro excluding the Moscow Central Circle and Moscow Monorail has 214 stations and its route length is 364.9 km (226.7 mi), making it the seventh longest in the world. The system is mostly underground, with the deepest section 84 metres (276 ft) underground at the Park Pobedy station, one of the world's deepest.