There is probably no ancient archaeological site anywhere in the world that has more relevance on today's world than Olympia. The history of the Olympic Games reaches back to the 8th century BC and continues today (OK, not without interruption...), so to visit Olympia should be interesting to everybody. Granted, at first the sight of ancient Olympia is a bit of a letdown, because there is really not a single structure still standing, mostly due to a number of earthquakes that covered the site under metres of mud. But then, seeing places like the site where the Olympic flame is lit every two years for the Games, and especially the original stadium (and being able to actually run there), is really quite amazing. You need a little imagination, but it's pretty easy to feel like an athlete of ancient times vying for an olive wreath there...

Definitely a must-see for anybody even slightly interested in Antiquity.