Petronas Twin Towers, Kuala Lumpur

At a dizzying height of nearly 457.2 meters (1500 feet), the Petronas Twin Towers, a pair of 88-story buildings, were the world's tallest buildings until 2004. Apart from offices, these awesome towers also house a state-of-the-art concert hall—the Petronas Philharmonic Hall, home of the Malaysian Philharmonic Orchestra—as well as shopping arcades, restaurants, and a science museum. The designs on the towers are based on geometric patterns common in Islamic architecture. Special features of the towers include the double decker skybridge between the 41st and 42nd floors and double decker elevators. Admission is free, however tickets are limited and issued daily on a first-come-first-served basis.