The mantle extends from the base of the Earth's crust down to the outer core, a distance of about 2,900 kilometers (1,800 miles).

Here's a breakdown:

* Crust: The outermost layer, about 3-50 km thick.

* Mantle: The thickest layer, about 2,900 km thick.

* Outer Core: A liquid layer, about 2,200 km thick.

* Inner Core: A solid ball of iron and nickel, about 1,220 km thick.

So, the mantle extends from about 3-50 km down to about 2,900 km, making it a very significant part of Earth's structure.