Cartagena is a port city on Colombia’s Caribbean coast. By the sea is the walled Old Town, founded in the 16th century, with squares, cobblestone streets and colorful colonial buildings. With a tropical climate, the city is also a popular beach destination. Reachable by boat are Isla de Barú, with white-sand beaches and palm trees, and the Islas del Rosario, known for their coral reefs.