The Longest Mountain Range Is Underwater

Think the Rockies or Himalayas are Earth’s biggest mountain ranges? Think again. The Mid-Atlantic Ridge is the longest on the planet—stretching 40,000 kilometers (25,000 miles) beneath the ocean, longer than Earth’s circumference.

This massive underwater range runs down the center of the Atlantic like a giant zipper, where tectonic plates pull apart and new ocean floor forms. It’s a geological hotspot, home to underwater volcanoes and hydrothermal vents that support bizarre deep-sea life, like tube worms and blind shrimp.

In some spots, the ridge rises above the waves—Iceland sits right on it, where you can literally stand between two continents.

Mostly hidden below the ocean, the Mid-Atlantic Ridge steadily reshapes our planet from the seafloor up.