A district of Mexico City, Xochimilco is known for its canals and chinampas, a farming system developed by the Aztecs to cultivate crops using the surrounding lakes. A UNESCO World Heritage Site, the Floating Gardens of Xochimilco harness unique agricultural techniques still in use today.

Established in 1521 by the Spanish, Old San Juan is the oldest city in the United States and its territories. There you'll find colonial architecture, impressive fortifications, cobblestone streets, open plazas, and hidden patios. Nearby, el Yunque National Forest is the sole tropical rain forest in the U.S.