Sin City's LEED Jackpot

Las Vegas must be feeling guilty about all the unmentionable things that happen (and stay) there. CityCenter, its latest monument to hedonism, is billing itself as one of the world's largest sustainable developments.

Opened last month, the MGM Mirage-owned complex has earned gold and silver LEED ratings for the buildings housing its hotels, restaurants, shops, and condos. Its energy practices save enough each year to power 7,700 homes, its construction reused 230,000 tons of waste (including 80 percent of the razed Boardwalk Hotel), and its landscapers opted for indigenous flora. There's also preferred parking for alt-fuel cars, a bicycle valet, and a fleet of natural-gas-powered limos.

--Avital Binshtock