These are the only hot pools in the town proper. A community project built in 1928, they are named for the Virgin Mary, who is said to have come here to dip her own feet. Some baths are cold, others warm and one reaches an intense 42°C (118°F). The rooftop pools have lovely views of a nearby waterfall. There are two locations; the 'old' pools at the top of the street, and the newer building below, which is open Wednesday to Sunday ($6/3).
Check out the ojo del agua, where the water, heated by the volcano, gushes from the earth at a scorching 50°C (122°F). A minor annoyance are the constantly blaring boleros from the sound system, which makes it a bit less tranquilo for gringos.
At the time of research, a $6.2 million construction project was underway to expand the complex to create one of the largest thermal baths in South America. A total of more than 10 separate pools will include a large swimming pool with slides and a wave machine.