Which city has the most elaborate subway system?

Seoul, South Korea's subway is the world's largest metro subway system with 315.8 miles (508 kilometers) of track. Beijing, China, is next, with 275 miles (442 kilometers); Shanghai, China, with 272 miles (437 kilometers); and then London, England's underground subway system, called the Underground, the world's oldest underground system (it was inaugurated in 1863). It has 250 miles (402 kilometers) of track. New York City's rapid transit system, built in 1904, rounds out the top five, with its 209 miles (337 kilometers) of track..

The London subway systemcommonly called the Undergroundhas over 250 miles (400 kilometers) of track and services three million people daily.