I don't know where to start... There's so much!!! It is the region with the richest history in the world - where you can walk through millennia of history, visit the oldest cities in the world, Roman monuments, traces of the Crusaders, etc.
Visit places that are the birthplace of the world's three religions - Judaism, Christianity and Islam - and where their most sacred places are. Walk the streets of Jerusalem or Bethlehem. You can understand the complexity of the region here, which is so much talked about.
Enjoy the charm of the Orient, excellent cuisine and much more.
Let me say what I think: Everyone should visit this country at least once in their lives! :)