The Moscow Metro in Moscow, Russia, is the world's most heavily used metro system, with 3.2 billion passenger rides a year. It is well known for the ornate design of many of the stations, containing stunningly beautiful examples of socialist realist art. Inaugurated in May 1935, the Moscow Metro network currently has 277.9 km of route length, 12 lines and 171 stations, and on a normal weekday (according to the annual report 2004) it carries 10.05 million passengers. Passenger traffic is considerably lower on weekends bringing the average daily passenger traffic during the year to 8.745 million passengers per day.