I agree, to see history as shown in books up close and personal leaves a lasting impression. Santorini is in excavation of the buried "Atlantis" they think, that is very very cool. We also just visited Tunis/Carthage, where the Romans crushed it into the ground and poured salt and lye to kill it off, only to rebuild on the Med was more than amazing. History in hand, very exciting.
To explore the world. On my list Costa Rica, Puerto Rico, Abijan, Ivory Coast, Italy...Just to experience different cultures and appreciate them for who they are and what their day to day life of survival means.
I love to travel the Far East. Just buying a ticket to a major City (Bangkok, Manila) and winging it from there. I've seen some amazing things that way. People are usually very friendly. Lots of tropical beaches. Travel changes you and your outlook on life. There's nothing like it.
There are many places on my list, but I would have to say that probably Tibet would be the ultimate. Perhaps one day to climb a mountain and meditate in a monastery there. Africa and Australia for the wildlife...