The movement of tectonic plates. These plates are large slabs made of the crust and and the rocks of the upper mantle.

Initially, there was a supercontinent:

Then because of the movement of the tectonic plates , the crust broke up from some places. And drifted off to form new continents.

At some places, the plates collided where large mountain ranges formed, such as the Himalayas.

Plates are just slabs on which landmasses rest:

These plates are constantly moving (even now as you read this answer), albeit at the rate of a few centimetres each year.

But over millions of years this movement shifts whole continents to thousands of kilometres apart.

This process is called .

Sometimes, they move much faster, causing earthquakes and volcanoes. But they are on the move every second.

You might start to wonder why they move? Good question.

The layer, under the crust , the mantle consists of some liquid rocks. (the core isn’t the only place where these are found).

So there is a lot of heat inside the mantle and that causes convection currents . Hot rock rises, gives off some heat, then falls. This creates swirls of moving liquid rock under the earth’s crust.

This movement of the mantle, causes the plates and the crust on top of them to move as well.

This is currently how the world looks:

But because of the movement of the plates, this map will change very significantly over the next millions of years.