This photograph of Machu Picchu has an amazing level of detail in it: you can zoom in so far that you can see the expressions on peoples faces. This Picture was taken using a 1.5 Gigapixel camera by Scott Howard, the same photographer who did a 720 Megapixel shot of Sydney in September 2006.

Stats:
Total Resolution 1500 MegaPixels (approx 60,000 x 26,000 pixels)
Camera Used Canon 10D, Canon 100-400L lens
Total Photos Used 404 (95% at 400mm, 5% at 100mm)
Time to take Photos 65 minutes
Software Used to Create Image Autopano Pro using SmartBlend
Time to Render Image Approx 11 hours
Final Image Size 13.5 GB!
Web Viewer Software Zoomify, with 31,805 demand-loaded images

You can find the Photo Here.