Home to the Pope and Michelangelo's Sistine Chapel, Vatican City draws 6 million pilgrims and tourists every year.

Walking Jerusalem's ancient stones is walking through 3,000 years of civilization, conflict, devotion, and human longing.

Since 1858, the small Pyrenean town of Lourdes has been one of the world's most visited Catholic pilgrimage sites, famous for its healing waters.

Perched atop impossibly tall rock pillars, the monasteries of Meteora are one of Christianity's most awe-inspiring — and unlikely — holy sites.