Here's why:

* Circumpolar Stars: These are stars that never set below the horizon as viewed from a particular location. They appear to circle around the celestial pole.

* Earth's Rotation: The Earth's rotation causes the apparent movement of stars across the sky.

* Celestial Poles: The Earth's axis of rotation points towards the celestial poles. At the North Pole, the North Star (Polaris) is directly overhead and all stars appear to circle around it. Similarly, at the South Pole, the South Celestial Pole is overhead, and all stars appear to circle around it.

The further away you are from the poles, the fewer circumpolar stars you will see. For example, at the equator, no stars are circumpolar.