Opened in 1938, chronologically it became the third line. There are twenty stations on the Zamoskvoretskaya line, and it spans 36.9 kilometres (22.9 mi), roughly crossing Moscow in a north-south direction. A normal trip along the entire line takes 52 minutes, with the trains on the line averaging 42 kilometres per hour (26 mph). While most of the line is underground, there are some pockets of surface-level or above-ground track, mainly at the point where the line crosses the Moskva River. The Zamoskvoretskaya line contains many examples of original Moscow Metro architecture