Here's a breakdown:

* The Mid-Ocean Ridge: This is the longest mountain range on Earth, spanning over 40,000 miles (64,000 km). It's submerged beneath the ocean and winds its way through all the major oceans.

* Formation: The Mid-Ocean Ridge is formed by tectonic plates pulling apart from each other (a process called seafloor spreading). As the plates move, magma from the Earth's mantle rises and solidifies, creating new crust.

* Volcanoes: The Mid-Ocean Ridge is a hotbed of volcanic activity. Underwater volcanoes constantly erupt, adding to the mountain range.

* Important Note: The Mid-Ocean Ridge is not just a single mountain range, but rather a system of interconnected mountain ranges that create a continuous chain around the globe.

Let me know if you have any more questions!