Stars That do not Set
Remember you cannot see below your horizon. Consider yourself exactly at the North Pole. You will see all the stars in circular trajectories around Polaris, that you can see as your Zenith is on Polaris. If you are exactly in the Equator, all stars are rising in the East and setting in the West. But if you are located somewhere in a latitude in between the North Pole and the Equator, you will see some of the stars rising and setting, and some stars that never will set for your latitude.
The following video, will help to understand how your latitude on Earth determines what stars you can observe that do not rise and/or set.
http://www.showme.com/sh?h=YzwOyUC
AstroDidactics 