Created by combining two wide-angle photographs taken from a balloon, this June 2005 panorama shows a 360-degree view that hasn't been seen by the general public since the 9/11 attacks destroyed the original World Trade Center towers. The new tower will include a 15-story concrete base, reinforced walls, and wider stairways to make it more resistant to attacks.

(Also see "9/11: Six Tech Advances to Prevent Future Attacks.")

The wire-tethered, unmanned balloon was released from a trailer at ground zero and raised to a height of 1,376 feet (419 meters) above ground—the elevation of the planned observation level in One World Trade Center. After verifying its height with a laser rangefinder, the balloon's cameras were triggered remotely.

"We rehearsed [the balloon's