In my personal experience, Draco is one of the most demanded constellations at observatories, and is often the hardest to spot without guidance. Snaking across Ursa Major and Ursa Minor, there is much debate over how this dragon won its place in the sky.

 

One of the most popular beliefs comes from one of Greek's most popular myths: "The Twelve Labours of Hercules." The eleventh labour of Hercules tasked him to retrieve the golden apples of Hesperides, but he did not know where Hesperides was. However, he knew that Atlas, who bared the weight of the world on his shoulders (literally), would know where it was, so he asked the titan for his help. Atlas presented two problems: 1) he could not simply drop the world, and 2) the gates of Hesperides were guarded by a giant serpent (Draco). Hercules first threw his spear at Draco, killing him, and then took the world onto his own shoulders. Atlas retrieved the apples for him and then, reluctantly, resumed his burden. For this, Atlas was rewarded by Hera, who hung the serpent in the stars for him.