An architectural structure of the Mycenaean civilization, a pointed dome built up of overhanging (corbeled) blocks of conglomerate masonry cut and polished, often with an alley or approach and a great door. The rich or noble of the Bronze Age were buried in these sometimes enormous, perfectly proportioned vaults though they were built in the Shaft Grave Period as well, perhaps first in Messenia in the 16th century and then in Greece by the middle of the 15th century. The tholos tomb has three parts: a narrow entranceway, or dromos, often lined with fieldstones and later with cut stones; a deep doorway, or stomion, covered over with one to three lintel blocks; and a circular chamber with a high vaulted or corbeled roof, the thalamos. Most tholos tombs have collapsed, often when the lintel cracked and gave way, and their contents have largely been looted.