Deep underneath New Zealand and New Caledonia is a large region geologists say was once another continent, which broke off from Australia 60-85 million years ago.
Named "Zealandia", the continent is 94% submerged under water and was originally part of Gondwana, an ancient supercontinent made up of Antarctica, Africa, Australia, South America, Madagascar, the Arabian Peninsula, and the Indian subcontinent.
A recent report from the Geological Society of America is the first peer-reviewed assessment of Zealandia, despite the sunken continent having been the topic of discussion since the '90s.
Zealandia is the world's youngest and "seventh-largest" (which is a nice way of saying second-smallest) continent. It has 4.9 million square kilometres of landmass, most of which is underwater.
The land mass sits just 25km from the Australian continental crust, spanning across the Cato Trough off the northeastern coast of Australia. The new continent takes in New Zealand, New Caledonia, and the Australian territories of Lord Howe and Norfolk islands.