A constellation in the northern hemisphere, also known as the Great Bear, or the Big Dipper.

Mythological Background:

According to greek mythology one day the Godfather Zeus saw a beautiful girl, the nymph Kallisto, and fell in love with her. But Kallisto was one of the virgin followers of the virgin goddess Diana, the huntress. So Zeus took the form of Diana to approach Kallisto and managed to make love to her.
Once Diana saw what had happened (Kallisto was obviously pregnant, when Diana and all her nymphs take a bath), she sent Kallisto away. Even worse, Hera, the wife of Zeus heard about Kallisto and her new born son Arkas and become terribly jealous. In her anger she turned her into a bear.
Years later Kallisto, still a bear, met her son Arkas, but was of course not recognized by him. In his fear Arkas tried to kill the bear, but Zeus himself took both of them an placed them between the stars and made them two neighbouring constellations.
When Hera saw Kallisto glittering with the stars she furiously went down to the ocean to meet Thethys and Oceanos. She told them the story and asked a favour: that the bear never ever be able to reach the water. And indeed, in the northern hemisphere, the constellation of the Great Bear never touches the ocean.

From http://www.seds.org/Maps/Stars_en/Fig/ursamajor.html