Bibliophiles will delight in this musty monastery's huge library, which contains more than 20,000 dusty books and maps; the oldest volume dates to 1494. Scholarship was an integral part of the Franciscans’ order; the library is open for supervised visits, just ask at the entrance.
Also on the premises is a well-known museum of Amazonian artifacts (including preserved jungle animals) collected by the missionaries, and an extensive collection of pre-Conquest artifacts and religious art of the escuela cuzqueña (Cuzco school).
The monastery was constructed on the west side of the Río Chili in 1648 by Franciscan friars, though now it has been completely rebuilt. Guides speaking Spanish, English, French and Italian are available; a tip is expected.
From the Plaza de Armas, it's an easy 10-minute walk across the river over pleasant Puente Bolognesi on the way to Yanahuara.