A working Franciscan convent hidden behind a plain facade two minutes from Puerta del Sol — one of Spain's great surviving Habsburg-era interiors, and a startling contrast to the modern shopping streets all around. The convent was founded in 1559 by Juana of Austria and quickly became the religious refuge of choice for Spanish royal women and their European cousins.
The interior tour (guided, in Spanish or English, limited group size) walks through the cloister, a sequence of chapels, a remarkable painted staircase by Spanish baroque artist Antonio de Pereda, and rooms hung with Flemish tapestries woven from Rubens cartoons. Entry €8. Tours run every twenty minutes; book ahead online. Closed Mondays. About 90 minutes for the full visit.