The Iglesia de San Francisco is among the oldest churches in Potosí, founded by Franciscan friars in the mid-16th century and rebuilt in its current form in the 18th century. The stone facade blends baroque ornamentation with indigenous artistic elements — the hybrid style known as mestizo or Andean baroque — and the interior is particularly rich, with elaborately carved wooden choir stalls and a collection of colonial paintings and silver objects.
The attached convent is open to visitors on guided tours and includes a cloister, a small museum of religious art, and access to the church roof, from which you get an unusual view across the terracotta rooftops and baroque bell towers of the colonial city toward the imposing bulk of Cerro Rico. The tour is worth the modest fee; the church on its own is free.