Dolmens are collective funereal monuments that correspond, generally, to the second phase of regional megalithism; they were built, for the most part, at the end of the Neolithic, less than six thousand years ago.
The funeral megalithic monuments that came before dolmens were formally similar although smaller in size and without a corridor and corresponded to individual burials.
The Large Zambujeiro Dolmen is, probably, the tallest in the world, with large granite supports that reach up to 6 metres in height. The stone structure of the monument is made up of a chamber defined by six supports (plus a closing stone over the entrance to the chamber) is a long corridor. The group was covered with monolithic covers; the covering slab of the chamber currently lies over the mound, on the western side.
The monument also preserves a large part of the mamoa, the small mound of stones that covered and originally hid, on the outside, the stone structure. On the edge of the mound a containment ring was built with fixed supports.
On the outside of the support that flanks the entry, to the South side, several sinuous parallel lines can be seen that are arranged longitudinally and which are one of the relatively frequent themes on menhirs in Alentejo and Algarve.
The monument’s currently hazardous state is the result of an old intervention that, due to having removed part of the mamoa drastically reduced the stability of the group of rocks; it was therefore necessary to build a provisional covering and stabilise some of the more sensitive points of the structure, while a more definitive recuperation of the monument is not possible.