This year in school we read a book called The Art of Travel by Alain de Botton. It considers the reasons we travel, and the effects of art and literature on our desire to travel. I would recommend it if you enjoy intense philosophical musings and incredibly detailed descriptions.
Basically, de Botton concludes that we travel as a result of other factors in our life. This might be a book we read once set in the deserts of Africa, a painting of a farm in England, or a travel brochure with a heavily Photoshopped image of a palm tree. Other people describing their own travels can also inspire us to pack our bags and head off.
De Bottons second and more interesting conclusion was about how we experience the destinations we travel to. He relates how, on a holiday in Barbados, he remained relatively unaffected by the beautiful beaches and lush rain forest, being instead occupied by concerns about a friend and work stress. He decides that our experience of travel is mainly affected by our expectations of the destination.
De Botton comes up with interesting ideas, but he doesn't completely explain our desire to travel- that is left to the individual to discover themselves.