Mnajdra is a megalithic temple complex found on the southern coast of the Mediterranean island of Malta, dating back to the fourth millennium BC. It is one of the most ancient religious sites on Earth. The unique, easterly orientation of Mnajdra above-ground temple suggests that the temple may have served as one of the world’s oldest solar calendars. On the Equinox days, a ray of sun enters the temple and lights up its main axis. On the Solstices, sunlight illuminates the entrance chamber’s megaliths.