2 Euros Hypogeum of Ħal-Saflieni

The Hypogeum of Ħal-Saflieni is a subterranean Neolithic temple complex in Paola, Malta, dated to roughly 3600–2500 BC and discovered accidentally in 1902 by workers cutting cisterns for a new housing development. The site was quietly excavated — and partially damaged — before authorities were fully informed, a fact that still irritates Maltese archaeologists. UNESCO inscribed it in 1980, one of the first such designations in the Mediterranean. Visitor numbers are now capped at a strict daily limit to prevent humidity damage to the ochre paintings inside.