The Hypogeum of Paola, Malta, literally meaning "underground" in Greek, is a subterranean structure dating to the Saflieni phase (3000-2500 BC) in Maltese prehistory. Thought to be originally a sanctuary, it became a necropolis in prehistoric times, as proven by the remains of more than 7,000 individuals that have been discovered during the course of the excavation. It is the only prehistoric underground temple in the world. The Hypogeum was depicted on a 2 cents 5 mils stamp issued in the Maltese Islands in 1980 to commemorate the acceptance by UNESCO of this unique structure in the World Heritage Site list. It was closed to visitors between 1992 and 1996 for restoration works; since it reopened only 60 people per day are allowed entry.
It was discovered by accident in 1902 when workers cutting cisterns for a new housing development broke through its roof. The workers tried to hide the temple at first, but eventually it was found. The study of the structure was first entrusted to Father Manuel Magri of the Society of Jesus, who directed the excavations on behalf of the Museums Committee. Magri died in 1907, before the publication of the report. Following Magri's sudden death, excavation resumed under Sir Temi Zammit.