The CE d'Alcoi explored the Estret chasm for the first time, on January 24th, 1954, with Rafael Pla being the first speleologist who reached its base, followed by José Navarro Claudio Blanquer and Fernando Llovet from Pego. At that time the endeavour had a great impact because it was the second vertical chasm in the world, preceded only by La Pierre Saint-Martin.

Following the road from Pego to Ebo, it is necessary to go up to the mountain range of Pla del Molló, between the 10th and 11th kilometre. About 110 metres before reaching the 11th kilometre, take a track that opens to the right of the road. Following the path and after about 500 metres, the chasm in question can be seen to the left, on the right side of the ravine that is being walked along upwards, just beyond some terraced fields.

The mouth of the abyss is of large proportions, reaching 15 by 12 metres in surface area, followed by a wide tube. The walls of the northwest limit rise about eight metres above the opposite ones, although the mouth remains diffused with the abrupt lapiaz (or lapiés: weathered limestone surface).

The chasm is reached from the eastern edge. At first there are bushes, climbing plants and trees occupying the first 15 metres.

The topography is very simple, since it is a giant well, of which 127 metres are absolutely vertical. It has 142 metres of depth and an average width of 15 metres. The cavity, more or less quadrangular, is formed by practically vertical walls. Cut off at 15 metres by a very inclined platform in the south-southeast part, the rest continues vertically. At 60 metres, a new descending stepped platform appears in the east, of about 15 metres of flight, until reaching 72 metres. From here on, a bell formation, more than 25 metres long and 20 metres wide, opens up and reaches 110 metres.

The floor is 13 metres wide by 30 metres long, set out from north-northeast to south-southwest, with a debris cone, inclined towards the north-northeast. At this point it goes 142 metres deep from the upper pithead of the entrance. To the west, a big mudslide leads to a small room full of concretions, from which one can see a deep chimney formation that rises to the surface. To the east, ascending the wall, one reaches a small concretion terrace.