The mobile phone, or smartphone as we now tend to call it, has come a long way since its invention. To celebrate its 20th anniversary Japanese communications company NTT DoCoMo put together an actual display, illustrating the the evolution of its phone line.
While you probably can't go see the physical installment, you can see this picture. Sure, it doesn't show every phone every made by everyone and rather just the ones by DoCoMo, it still gives you a great look into the evolution of the device as whole, were it came from, and where it is now. Take a look over here: [Designboom]