Guggenheim Museum, Bilbao
Soon after it opened in 1997, critics hailed the dynamic, swirling titanium mass as one of the 20th century's great buildings. As the catalyst for the regeneration of this Basque city, the structure claims an intimate yet fluid connection with its setting: it hugs the curves of the Nervión River, its silvery "tail" emerging beneath a bridge like that of a giant metal fish.
Vals Spa, Vals, Switzerland
In a remote valley in southeastern Switzerland, the contemporary architect Peter Zumthor has elevated the ancient thermal bath to the realm of the sublime. Contrasts between light and shade, especially in otherworldly grottoes of quartzite shrouding softly lit pools, inform the experience. Incomparable Alpine views from outdoor spaces serve as a reminder that nature is the preeminent architect.
Ryoanji Temple, Kyoto
The former Imperial capital is filled with temples and gardens, but late-15th-century Ryoanji ("Temple of the Peaceful Dragon") stands out for its stark simplicity. Its walled-in courtyard contains nothing more than 15 large mossy rocks surrounded by a sea of raked gravel, the quintessential Zen garden.
Fallingwater, Bear Run, Pennsylvania
In 1991, the American Institute of Architects voted this 1939 house "the best all-time work of American architecture." Frank Lloyd Wright built it atop a rocky outcropping and extended the floors to reflect the ledges around it, redefining how architecture could be integrated with nature. The showstopper: a terrace daringly cantilevered over a rushing waterfall.