Built in 1636 around the room where the saint was born in 1515, this is the epicentre of the cult surrounding Teresa. There are three attractions in one here: the church, a relics room and a museum. Highlights include the gold-adorned chapel (built over the room where she was born), the baroque altar and the (albeit macabre) relic of the saint's ring finger, complete with ring. Apparently Franco kept it beside his bedside throughout his rule.
The elaborate chapel is lorded over by a baroque altar by Gregorio Fernández, which features a statue of the saint. There's also a modest basement museum dedicated to Santa Teresa, accessible from Calle Aizpuru.