The Great Dolmen of Zambujeiro is considered one of the largest structures of its kind on the Iberian Peninsula and is sometimes referred to as the "Cathedral of the Stone Age".

Research has dated this dolmen structure to between 4000 and 3000 BC.

The dolmen was discovered in 1964 when the 20-ton capstone was blown up and is now protected from erosion by a corrugated iron cover.

The megalithic cult building has a total diameter of around 50 m and consists of a polygonal chamber and a long corridor, which together are 19 m long. There was a stone pavement in front of the entrance. The width of the chamber, which is divided into quarters by vertical slabs, is five meters at ground level.

The dolmen was covered with a mound of earth six meters high and 70 meters in diameter. Today, the supporting stones protrude about six meters from the ground.