The Monasterio de Santa Catalina is the single most extraordinary place in Arequipa. Founded in 1579 to cloister the second daughters of wealthy Spanish families, it functioned for almost 400 years as a closed religious community, occupying a five-acre walled compound in the middle of the colonial centre. Most of the city was unaware of what it contained until the Vatican forced reforms in 1970 and the monastery opened its doors.
What you walk into now feels less like a building than a tiny, self-contained Andalusian town: blue and ochre-painted streets, fountains, plazas, kitchens with conical clay ovens, and the narrow cells where the nuns lived. The colour scheme alone justifies the visit. Allow at least two hours; longer if you take the included guided tour. Photography is encouraged. A small group of cloistered nuns still lives in a private section behind the visitor compound.