Saw this Vimeo video on Techcrunch from the makers of Wikitude which brings back the World Trade Center Towers as they were through augmented reality. This addition may be emotional but it also brings to light the potential for historical reference. Can you imagine what historians and archaeologists with the help from a GIS professional can bring to life? Think about the Mayan ruins in Central America or our fleet at Pearl Harbor before the attack. How about walking in ancient Greece as it were during the height of their civilization. You could scan the walls of ancient glyphs and view a restored version with the latest linguist theory on translation. It would bring forward a more engaging experience to the sites of great historical importance for both researchers and tourists. Heck, ANY location regardless of significance can restore history lost through modernization.