The vibrant, bustling city of Mumbai--formerly Bombay--is one of India's two major gateways, and a must-see part of any itinerary. On our recent tour of India, we flew into the other gateway, Delhi, and made Mumbai our last stop before returning to the U.S. However, if you fly in through Mumbai, you may suffer less culture shock than we did, since the city is more cosmopolitan than any of the other cities we visited, and is renowned as the country's financial nerve center. It still honors India's deep traditions and rich history, but Mumbai is working hard to define its future.