What did the Earth look like at the time of the world's last ocean?
More than 300 million years ago, before the arrival of the first dinosaurs, the Earth didn't have seven continents like it does today.
We've always known about these seven continents, but the Earth hasn't always looked the same.
Millions of years ago, in place of these seven landmasses, there was a single massive supercontinent called Pangea, itself surrounded by a single ocean: the Panthalassa.