Built in 1636 around the room where Santa Teresa was born in 1515, this is the epicentre of the cult surrounding the saint. 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 (macabre) relic of the saint's ring finger, complete with ring. Apparently Franco kept it at 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 basement museum dedicated to Santa Teresa, accessible from Calle Aizpuru.