What the subway looks like in 13 different countries around the world

Public transportation can be a great equalizer - no matter the city, riders can see all walks of life during a bustling morning commute. Photographer Stan Raucher has been influenced by the underground since he shot his first photos inside the Paris metro in 2007.

Since then, he's been snapping photos of commuters in cities across the world - from Shanghai to London. Instead of glamorous travel photos, Raucher's thoughtful subway images give viewers a glimpse of what every day life in like in these metropolitan areas: what people are wearing, how they're interacting, and, of course, what the interiors of the public transit systems look like across the world.

His new book, "Metro: Scenes from an Urban Stage" contains 50 photos that let viewers inside over 15 different transit systems. Ahead, a selection of images from Raucher's book, and his thoughts behind the work.