Largest Metro Systems You Want to Visit

Madrid Metro

Although Madrid is only the 50th most populous city in the world, its metro is the 6th longest with 182 miles of track dotted by 300 stations – With almost the same number of stations as Paris and even a larger total length – 293 km (182 mi), the Madrid Metro was first opened in 1919. It has “only” 500 million riders every year.