While cities may look different from each other at ground level, they're way different once you get underground.
It's mind-boggling to imagine your commute on one of the world's major subway systems, whether it's through St. Petersburg's tricked-out stations or in Stockholm, where the tunnels are basically art museums.
We asked readers to share their best shots of subways around the world -- and we must say, these stations are sleeker than we even imagined. (Can we step up our game, NYC?)
Take a look, take a ticket, and enjoy the virtual ride on subways 'round the world. Did we miss a shot? Tag your metro pics #huffpostgram to share with us.