Great Blue Hole
The Great Blue Hole is a giant marine sinkhole off the coast of Belize. It lies near the center of Lighthouse Reef, a small atoll from the mainland and Belize City. The hole is circular in shape, across and deep. It was formed during several episodes of quaternary glaciation when sea levels were much lower. Analysis of stalactites found in the Great Blue Hole shows that formation took place 153,000; 66,000; 60,000; and 15,000 years ago. As the ocean began to rise again, the cave was flooded. The Great Blue Hole is a part of the larger Belize Barrier Reef Reserve System, a World Heritage Site of the United Nations Educational, Scientific and Cultural Organization (UNESCO).
Bluestonehenge
Bluestonehenge or Bluehenge (also known as West Amesbury Henge) is a prehistoric henge and stone circle monument that was discovered by the Stonehenge Riverside Project about south-east of Stonehenge in Wiltshire, England. All that currently remains of the site is the ditch of the henge and a series of stone settings, none of which is visible above ground.