Complex sentence: Rano Kau is a tall extinct volcano that forms the southwestern headland of Easter Island, a Chilean island in the Pacific Ocean; it was formed of basaltic lava flows in the Pleistocene with its youngest rocks dated at between 150,000 and 210,000 years ago.
Split into simpler sentences: Rano Kau is a tall extinct volcano that forms the southwestern headland of Easter Island, a Chilean island in the Pacific Ocean. It was formed of basaltic lava flows in the Pleistocene with its youngest rocks dated at between 150,000 and 210,000 years ago.