Emperor Shah Jahan, in 1632, commissioned this most famous of all mausoleums for his favorite wife, Mumtaz. One of the greatest examples of Moghul architecture—a marriage of Hindu, Persian, and Islamic design—the Taj sits amid serene pools that reflect its unmistakable profile.
In 1960, President Juscelino Kubitschek moved Brazil's government from Rio to its new capital, a futuristic fantasyland where monumental buildings by Oscar Niemeyer march down the immense axis of Lucio Costa's master plan, defining the Modernist urban landscape.
Altes Museum, Berlin
The Old Museum, one of the first purpose- built museums to house a royal collection, was designed in 1823 by Karl Friedrich Schinkel. The façade's peristyle of 18 Ionic columns, inspired by the Stoa of Attalos, in Athens, demonstrates Schinkel's interest in ancient architecture and epitomizes Neoclassical style and 19th-century museum design.
This monumental temple, in use throughout its history, was erected by the Roman consul Marcus Agrippa in 27 B.C., rebuilt by Hadrian after a fire in about 125 A.D., and consecrated as a Christian church in 609 A.D. It stands as a pure expression of classical proportions; the coffered dome—with a heaven-gazing oculus at its apex—and colonnaded portico have inspired generations of architects.
Related: Rome Travel Guide
Hagia Sophia, Istanbul
The dome atop Constantinople's Church of Divine Wisdom, erected in 532 A.D., was the largest in the world until St. Peter's was completed 1,000 years later. In 1453, the conquering Ottomans turned the Byzantine church into a mosque, adding minarets and plastering over its elaborate mosaics. This confluence of cultures is now a museum—with its mosaics resplendently restored.
Chichén Itzá, Mexico
The tropical lowlands of the Yucatán Peninsula and northern Central America are dotted with Mayan and Toltec ruins. Few are as grand as Chichén Itzá. The site's pyramids, ball courts, and palaces, grouped around grand plazas, leave no doubt of the sophisticated civilization that thrived centuries before Columbus arrived.
Sir John Soane's Museum, London
Architect John Soane, designer of the Bank of England and the Dulwich Picture Gallery, rebuilt three adjacent town houses from 1792 to 1823 and filled them with his treasures—an Egyptian sarcophagus, Roman marbles, Hogarth's The Rake's Progress. Displayed chockablock, they now form part of a connoisseur's legacy in a museum that retains the character of a private house while its clever design accommodates a collector's zeal.
The Barcelona chair, an icon of 20th-century design, was born in a sleek, equally iconic masterpiece of Modernism in Montjuïc Park: the German National Pavilion at the 1929 Barcelona International Exhibition. Mies van der Rohe designed both, and the pavilion's space—enclosed by walls of glass, travertine, green marble, and golden onyx—embodies his concept of open- plan, while its colors and materials define the period's ideal of elegance.
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.