The building is literally carved into the earth to help fight against a storm as well as heat and cool more efficiently.
They're basically challenging the weather to try and take it down. Since the area can get hit by some pretty nasty storms the place was designed not only to withstand hurricane force winds but to also be self sufficient. It comes complete with potable water storage and back-up power production. You can also check this out over at my Thursday guest home, Fred Flare.