The architectural highlight of Arequipa is without a doubt the 425-year-old Monasterio de Santa Catalina (Santa Catalina 301, tel. 054/22-9798, www.santacatalina.org.pe, 9 a.m.–4 p.m. daily, US$8, guides work for a tip). The convent is a small city built entirely of sillar with a hundred houses, 60 streets, three cloisters, main square, church, cemetery, and painting gallery. More than 400 colonial paintings, mostly from the Cusco School, hang in a gallery that was once a homeless shelter for widows, single mothers, and homeless women.

As many as 175 nuns lived here during the 17th and 18th centuries, including the daughters of wealthy families who lived in private houses with up to four servants. Today, there are 29 nuns (oldest 96, youngest 21) living in modern quarters in the convent who subsist on tourist entry fees. The nuns were shut off from the rest of the city until 1985, when they became half-cloistered—meaning they can now leave and shop for food or visit relatives (up until that year, they only spoke with families through screened windows).

Photographers should visit late in the afternoon, when the light falls across the buildings at interesting angles.