The Hal Saflieni Hypogeum is a subterranean structure testifying the artistic and architectural accomplishments of Malta’s Neolithic society, spanning from around 4000BC to 2500BC. It was discovered during construction works in 1902. It was used both as a sanctuary and a cemetery. The bones of 7000 people have been found here (in bits and pieces).The monument is considered one of the essential prehistoric monuments in the world. Entrance is limited to 80 persons a day, and pre-booking a visit