Discovered by Barandiarán and Medrano in 1956 and excavated by them in 1964.

The chamber presents a polygonal plan and is made up of 10 sandstone slabs of extraordinary dimensions (5.75 mx 3.10 m and maximum height of 1.90 m). The corridor is configured based on five slabs, presenting a width of 1.20 meters and a height of 1.30 meters. This slab on the W side of the corridor, on which the deck rests, has abundant holes or bowls that seem to respond to art manifestations typical of megalithism. Around this the mound of stones and earth is arranged, which has been seriously affected by the cultivation of vines that have surrounded the monument.