Egyptian artifacts at the Ft. Lauderdale Museum.
Some of Davincis sketches at Windsor Castle.
Roman Walls at the Museum of London and the Tower of London. I liked being able to touch them. Makes it more personal and helps me really contemplate their sheer age.
Everything at the British Museum. But especially the Sutton Hoo items.
A moon rock at the Smithsonian. I liked touching that as well.