The Taj Mahal in the city of Agra is perhaps India's most famous landmark. In 1638, Emperor Shah Jahan began building it as a marble tomb for his beloved wife Mumtaz Mahal. With precious gems and stones pressed into its walls, the Taj Mahal took 22,000 workmen 22 years to complete. It is known as the eighth wonder of the world. (FRANS LEMMENS—GETTY IMAGES)