QUICK FACTS
Name: Indian Ocean geoid low
Location: Laccadive Sea, southwest of India
Why it's incredible: The huge gravity hole formed on the site of a prehistoric ocean.
The Indian Ocean "gravity hole" is the site of the deepest dent in Earth's gravitational field. It's a circular ocean region with a gravitational pull that's so weak, sea levels are 348 feet (106 meters) lower there than elsewhere on Earth. Discovered in 1948, the origins of this giant gravity hole — or geoid low, as it is technically called — remained a mystery until recently.
