The Ħal Saflieni Hypogeum is an underground structure that was made between 3600 BCE and 2500 BCE in Paola, on the island of Malta. It is believed that it was originally a sanctuary, which became a necropolis in prehistoric times. It is the only underground prehistoric temple in the world. It was closed to the public between 1992 and 1996 for restoration.
The Ħal Saflieni Hypogeum was discovered by chance in 1902 when workers who were cutting tanks for new homes broke the ceiling. The study of the structure was initially 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 excavation report. Following the unexpected death of Magri, excavations resumed under the control of the scholar Themistocles Zammit.