Population: Approx. 3,500
Why it's weird: Pretty much everyone lives underground
This tiny Aussie town is the world's primary source of high-quality opal gemstones, earning it the nickname "The Opal Capital of the World." Sounds tame enough. But decades ago, when miners first started pulling shimmering gems out of the ground here, they decided to beat the oppressive Outback by building their living quarters underground. These days, the methods for extracting opal may have improved, but the majority of Coober Pedy's roughly 1,600 residents still live like mole people, since the insulation provided by the rock walls save on AC bills in the summer and heating bills in the winter. Is this the next wave of design in New York City? Only time will tell.