World's Coolest Buildings

Caltrans 7 District Headquarters Replacement Building, Los Angeles

Architect: Thom Mayne/Morphosis

Why It’s Cool: Despite both a cumbersome name and less-than-glamorous function—bureaucrats plan freeway repairs in 13 stories of offices—Mayne’s silvery hulk feels airy and fantastic. Eco-friendliness explains some of the cutting-edge appeal: The southern wall is covered by photovoltaic cells that transform sunlight into electricity. And the western side boasts double-thickness glass that keeps interiors cooler than single panes could, thus obviating the need for much air-conditioning.

How to Visit: The public can’t go upstairs, but there is a ground-floor restaurant, Begin’s Cafe (213/620-9565; www.beginscafe.com), which offers sandwiches on reusable dishware instead of throwaway plates.