Catedral de Sevilla, Seville

Seville's Cathedral, the largest Gothic cathedral in the world, stands on the site of a former mosque. Its soaring arches, ornate chapels, and the Tomb of Christopher Columbus make it a cultural and religious landmark. Climb La Giralda, the former minaret turned bell tower, for panoramic views of the city. The cathedral's sheer grandeur makes it a must-visit.