Paganism is not one single religion. "Paganism" is an umbrella term which covers many different religions and spiritualities. Wicca is the most well known Pagan religion, but there are others like Druidry and Heathenry. There are many more, but these are the three that I am most familiar with.
This is something which I take for granted, but a while ago I was talking to a classmate and found myself explaining this little detail about Paganism. Her response? "I didn't know that! Ok, that explains a few things that I hadn't understood." Because of what she said I thought that it would be a fact worth sharing as a Pagan Values Month post. :)