The Paris subway system is the second oldest in the world and transports roughly 1.5 million people daily at modest fares.

The subway system runs over 214 km and stops at 380 stations. The network is so extensive that almost every building in Paris is within 500 meters of a subway station. Many of these stations are famous for their architecture, representing the Art Nouveau style.

Image: Parisian elevated metro | Photograph: Martin Bureau/AFP/Getty Images.