From the Daily Telegraph (UK) web site:
The predecessor to gap-year travelling was the "Grand Tour", a European travel schedule popular with young aristocrats in the 18th century. It's where the word "tourist" comes from.
It was created as both a chance for education and a rite of passage, taking in the greatest arts and sights that Europe had to offer. A tutor or guardian called a "bear-leader" accompanied the young men. The bear-leader was responsible for both teaching and restraining his charges.
The tour would start at Dover. From there, the gentlemen would sail to France, learn the subtleties of French etiquette, then travel over the Alps to Italy for a crash course in classical architecture and Renaissance art.
A sojourn in Greece followed, with the final leg taking in the Germanic countries. Here conditions were often so insanitary that a "tourist" was advised to carry a live pig in his luggage. The pig would be placed in the tourist's bed before dinner, so that by bedtime the bunk would be warm, and the bedbugs sated on pig's blood.