If humans land on Mars by 2037 as NASA hopes, they'll need cities modeled on ones that already exist in extreme climates on Earth.

Here are six high-tech (and a few low-tech) cities that would have a passing shot at survival in the Martian climate.

the barren playa of Black Rock Desert in Nevada,

is like a beta test for instant colonies

Already there is an international program devoted to simulating life on Mars in the arctic region.

A vast city that grew out of a harsh desert climate over the past two decades,

Much of Vegas is already under a dome, in the sense that most action on the strip takes place in vast, climate-controlled casino-malls.

Canada is an excellent analog for Mars. Cold and dry

a pueblo alone wouldn't work as a Martian colony, but pueblo-style dwellings with atmospheric controls, low to the ground and interconnected, made from thick Martian clay, might be just the ticket for a Martian city.