The oldest paintings in the world, in the extraordinary cave art of Altamira, Lascaux, and Chauvet.

Learning about the builder of Taj, the Mughal emperor Shah Jahan, and his beloved wife Mumtaz Mahal, for whom it was built.

The Great Barrier Reef is one of the world's natural wonders, drawing travelers to its shimmering, multicolored coral reefs, teeming with fascinating marine life.

The Mogao Grottoes, dug out of cliffs in the desert of northwestern China, contain one of the most dazzling collections of Buddhist art in the world.

The citadel of Persepolis was the capital of the Achaemenid Empire for nearly 200 years.

The moai, the colossal statues of Easter Island, are a testament to human innovation.