On July 19, 2003, The Invisable O asked the HBO forum if anyone had ever mapped the entire surface of Halo. BOLL decided to see what he could do. First, he created a partial panorama inside the ring from the Pillar of Autumn level to see if the texture tiled. It does. (Directions on how he accomplished this are here.)
He then came up with a way to actually capture the the texture (read this for details), and extracted a single tile.
Click image for much larger version (5000x200, 196K)
Not long afterwards, he went back and grabbed the backside tile, as well:
Pretty impressive work, all around!