Scientists uncover colossal mountains 100x taller than Everest hidden 1,200 miles beneath Earth's surface, reshaping our understanding of Earth's mantle and inner layers.

Two hidden mountains, more than 100 times larger than Mount Everest have been discovered deep underground. The two ‘islands of rock’ each measure more than 620 miles / 998km tall, dwarfing anything found on Earth’s surface and making Mount Everest look like an anthill.

The vast mountains are believed to be at least a billion years old, but they could date back as far as four billion years to the birth of our planet.

Deep within Earth’s mantle lie two enormous regions, often referred to as "islands," which are the size of continents.