The visit is guided and has an approximate duration of 45 minutes. For reasons of conservation, there is a maximum quota of people per session and day. In low season (from November 1st to Febrery 29th) the visit is done in groups of 8 persons maximum, and season medium and high (from March 1st to October 31st), in groups of maximum 7 people. It is advisable to book at least one day in advance via website, email or phone. The reservation must be formalized at the box office at least 10 minutes before the start of the visit in the visitor reception centre, located at the mouth of the cavity. During the visit the use of comfortable footwear that does not slip and outerwear is recommended.