These warm caves on the northeast edge of town have some impressive stalagmites, stalactites and other rock formations, making the one-hour, 17-chamber underground journey fun, especially for kids. To get there take either a taxi (M$70) or a ‘Nombre de Dios Ojo’ bus (M$6) from outside Posada Tierra Blanca on Niños Héroes. Ask the driver to tell you when to get off.