Basilica de San Isidro

Before the Almudena Cathedral was finally consecrated in 1993, this was effectively Madrid's cathedral — the acting seat of the archbishopric for nearly two centuries. Built between 1622 and 1664 by the Jesuits as part of the Imperial College, the Basilica de San Isidro is a masterpiece of Spanish Baroque architecture that served as Madrid's pro-cathedral from 1885 until 1993. For over a hundred years, every major religious ceremony in the capital happened here.

The church is dedicated to Madrid's patron saint, San Isidro Labrador — a 12th-century farmer who, according to legend, was so devout that angels plowed his fields while he prayed. His incorrupt body (miraculously preserved, the faithful say) was kept here for centuries, along with that of his wife, Santa Maria de la Cabeza. The couple is one of the very few married pairs in Catholic history to both be canonized.

The Jesuits built the church and the adjoining Imperial College as a showcase of Counter-Reformation grandeur. When Charles III expelled the Jesuits from Spain in 1767, the church was reassigned to the secular clergy and the college became a prestigious school. The interior is classic Jesuit: a single nave, barrel vault, side chapels, and an overwhelming retable behind the altar. The dome rises 55 meters from the floor and fills the nave with diffused light.

Look for the Chapel of San Isidro, added in the 18th century, with its elaborate frescoes and the silver urn that once contained the saint's remains. The basilica doesn't get the attention that flashier churches receive, but for almost four hundred years, this was where Madrid came to pray, to mourn, and to celebrate — the spiritual heart of a capital that kept promising to build a proper cathedral and never quite getting around to it.