its subsequent destruction likely shielding the lower structure from discovery for thousands of years. Nothing remains of any potential enclosure that would have marked the entry to the Hypogeum. The underground structure may have originated from a natural cave, expanded over time by cutting directly into the rock with crude tools including antlers, flint, chert and obsidian. Burial chambers in the upper level of the Hypogeum date from the early phases of the Maltese Temple Period, with lower chambers dating from later. The site may have first been used as early as 4000 BC, and was likely used until around 2500 BC, based on pottery sample analysis and examination of human remains. The temple structure uses a careful direction of light from the surface to penetrate into the lower chambers, with intricate patterns painted on portions of the ceiling with red ochre, following motifs of spots, spirals and honeycombs. One of the main chambers, called "The Holy of Holies", appears to be oriented such that light from the winter solstice illuminated its facade from the original opening above. A resonance niche cut in the middle chamber, called the Oracle Room, was possibly designed to project chanting or drumming throughout the rest of the Hypogeum. A broad range of objects were recovered from the site, including intricately decorated pottery vessels, stone and clay beads, shell buttons, amulets, axe-heads, and carved figures depicting humans and animals. The most notable discovery was the Sleeping Lady, a clay figure thought to represent a mother goddess. The figures range from abstract to realistic in style, with major themes thought to be related to veneration of the dead and spiritual transformation. Complex artistic techniques are also represented, as in the case of a single large pottery bowl which utilized both naturalistic and stylized themes, with one side realistically depicting bovines, pigs and goats, and the other side representing hatched animals hidden within complex geometric patterns. It is guesstimated that the remains of 7,000 individuals were found in the Hypogeum, and though many of the bones were lost early in excavation, most of the skulls were deposited at the National Museum. A small percentage of the skulls have an abnormal cranial elongation, similar to priestly skulls from Ancient Egypt, fueling speculation about the people who occupied the Hypogeum, and their practices and beliefs. Structure The Hypogeum is constructed entirely underground and consists of three superimposed levels hewn