It’s a picture of the President Barack Obama’s inaguration. What makes it unique is that it’s an extremely EXTREMELY high resolution picture, which allows you to zoom in to the entire picture.
What I find most fascinating is looking into the crowd at some of the people’s expressions and faces. They have no idea they’re being watched.
The picture first provides you with a panoramic shot of the inaguration and it’s attendees. Then, the controls on the left – similar to Google Map’s controls – allow you to zoom in, out and pan in all directions.
When you zoom in, you can view objects and people with remarkable clarity for the distance they’re being shot from.
UPDATE: It looks like you can also purchase the equipment from http://www.gigapansystems.com/ that will allow you to take a normal digital camera and turn it into a GigaPixel picture.