Tradition and trendiness meet in this bustling Indian city.

Mumbai contains both the world's first billion-dollar home (located in the tony neighborhood of Malabar Hill) and one of Asia's largest slums. And this paradoxical city by the sea, already 18 million strong, keeps growing: A major airport restoration is in progress; the Bandra-Worli sea-link bridge is set to open in early 2009 to relieve the city's tremendous traffic problems. "The best reason to visit Mumbai," says Suketu Mehta, author of Maximum City: Bombay Lost and Found, "is to see how a city can survive, and thrive, against every rational expectation."