A photographic survey of the world's metro gateways.
No two subway systems are identical, and neither are their station entrances.
Across the world, cities' underground entrances represent a local (or more often, regional) flavor. There are the sleek (see Bilbao and Helsinki), the subtle (Lisbon and Liverpool), the somber (we're looking at you, Washington, D.C.), and the kind of sad, like the ones in Nizhny Novogrod.
This week, we surveyed subway entrances from all over the world, and distilled them down to the 30 different entrances from 25 systems presented below. We're curious to hear what your impressions are based on these images, so be sure to leave your thoughts in the comments: