I'd say my 6 week jaunt in Greece when I was 21...it was a great adventure- chasing girls, smoking hashish, a brush with death on a scooter, running out of money and sleeping in a cave, making fast friends, island hopping, seeing the ruins in Athens, getting in a fight, cheering on Denmark with a bunch of Swedes in the Cup final, getting drunk on Ouzo, reading a fantastic book, getting the best tan I've ever had, eating a copious amount of souvlaki sandwiches, all in the most amazing, ancient, sun soaked setting...and not knowing that it would be the highlight of my life.