Located in the village of Lotofaga (population: 1,089) on the south coast of Upolu island in Samoa, is the To Sua Ocean Trench. An all-natural swimming hole with a large ladder and small dock, visitors can pay a fee ($15 for adults, $6 for children 7-15, free for kids under 7) to access the 30 meter (98 ft) deep hole.

The island of Upolu was formed by a massive basaltic shield volcano. With an area of 1,125 km2 (434 sq mi) and a population of 135,000, it is the second largest in geographic area and the most populated of the Samoan Islands. Samoa gained its independence from New Zealand in 1962.

To Sua Ocean Trench is open all week from 7am to 6pm.

[Sources: Samoa Tourism, 1, 2, 3]