Artificial caves of Alapraia
They are situated in the centre of the suburb of Alapraia in Estoril , Lisbon District , Portugal and are believed to date back to the last quarter of the 4th Millennium BCE and to have been used as a necropolis for over one thousand years . 
<triplet> Estoril <subj> Portugal <obj> country <triplet> Lisbon District <subj> Portugal <obj> country <triplet> Portugal <subj> Lisbon District <obj> contains administrative territorial entity