Complex sentence: Actun Tunichil Muknal is a cave in Belize, near San Ignacio Cayo, notable as a Maya archaeological site that includes skeletons, ceramics, and stoneware.
Split into simpler sentences: Actun Tunichil Muknal is a cave in Belize, near San Ignacio Cayo. As a Maya archaeological site, ATM is notable for its skeletons, ceramics, and stoneware.