Here's why:

* Gravity is a force of attraction: Every object with mass exerts a gravitational pull on every other object with mass.

* Earth's mass is huge: The Earth has a very large mass compared to objects on its surface. This means it exerts a strong gravitational pull.

* Center of mass: The gravitational pull from all parts of the Earth effectively combines towards the center of the Earth.

Therefore, regardless of where you are on the Earth's surface, the force of gravity will always pull you downwards, towards the Earth's center.