Puig y Larraz (1896) mentions an “Avench de Pratdip”, taking the data from a report on earthquakes (Bayo, 1845). From the brief description he gives, we understand that he is not referring to the avenc de Pratdip (Avenc del Pla), but to the cave of the same name. According to Joan Ferraté (1918) the first exploration took place on 12 March 1911 by members of the Agrupació Excursionista de Reus, who did not go beyond the zone of the first shaft. The second exploration was carried out on 27 October 1935 by a large group of members of the Club Muntanyenc Barcelonès and although they make an exhaustive reconnaissance of all the galleries of the lower zone of the entrance shaft, they do not find the access to the lower zone of the cavity. We have practically no further documented news, we only know by hearsay that speleologists from Reus visited it often around the decade of the 1960s and that they had discovered a new shaft that gained depth for the pit. It also seems that the people of Reus began to call it Avenc del Pla, because it is located in the Pla de l'Avenc. These data are confirmed and documented after the exploration by the SIE – CEA at the end of 1972. It should be said that according to the most current geo-references, the pit is located in the municipality of Pratdip, contrary to the data of the most “recent” surveys: SIE (1972) and ERE-CEC (1974) which placed it in the municipality of Colldejou. Toponymy: We have had a certain dilemma when choosing the name of the cavity for its cataloguing. Since ancient times its explorers have called it Avenc de Pratdip, but for some years now the most common name for it is Avenc del Pla. Finally we have opted for the first in consideration of the history of the pit. Unlike its neighbour, the Cova d'en Blai, d'en Xoles or del Mas Monet, which the first speleologists who studied it called Cova de Pratdip, it should be said that the previous names (Blai and Xoles) were in common use in the area to name it before the speleological explorations.