In Japan, there are special metro cars reserved especially for women.
It is illegal to eat, drink, or smoke on the Washington D.C. metro because of the extra costs associated with cleaning the carpet. Yup, THE CARPET.
The Moscow metro is commonly regarded as having the most beautiful stations in the world.
In fact, there is a train in Moscow called the "Aquarelle Train" that displays replicas of famous works of art for its passengers to enjoy.
Joseph Stalin reportedly built a secret metro system (known as "Metro-2") to be used by the military in times of duress during the Cold War.
The London Underground is the world's oldest metro system.
The New York City subway — with 468 stations — is the largest subway system by number of stations.
The Seoul metro is the world's largest in terms of passenger-route length*.
The Arsenalna metro station in Kiev, Ukraine, is the world's deepest, at 346 feet (105.5 meters) underground.
The Copenhagen metro is a 24/7 driverless electric system with a sweet view.
The word "metro" actually comes from an abbreviated form of the "Paris Metropolitan".
The Hong Kong metro is equipped with 3G cell phone service, meaning passengers can access the internet even when underground.
There are currently only four cities on the African continent with metro lines.
The Pyongyang metro in North Korea costs 5 KP₩ (about $0.03) per ticket.