The entrance to this Tehran Metro station may be crowded, but it's nothing compared to the car traffic. The Iranian capital's subway system has four lines.
Tehran's subway system, like much of the city, is covered in art installations. The metro began operating in 1998 with three stations; there are now 70 stations throughout the city.
The system transports nearly 2 million people per day, according to the Tehran Urban & Suburban Railway Operation Co.
The Metro is incredibly clean -- no hardened gum, or even dust, to be seen.
A man sells olives for hungry commuters outside one station.
A man and his young son watch the tunnel go by.
Any prepared urban traveler comes with snacks -- in this case, sunflower seeds.
Not missing an opportunity, the subway's handles double as ad space.
The subway system has cell phone coverage both in stations and tunnels.
A man sells balloons -- or tries to sell balloons -- on a train full of mostly uninterested commuters.
This is what he is up against -- a public service announcement warning commuters against buying from subway salesmen.
Driving is "a waste of time and a waste of money," says Nima, center; using the Metro is much easier.