It's the Rock. Alcatraz. You can see it here at the left of the frame;
to the right of center, you can barely see one of the supports for the Golden Gate
Bridge in the deep background.
This site was originally designed in 1996 using Adobe PageMill.
The current incarnation is a back-to-basics type of site, making extensive
use of server-side includes to create page geometries and interactive
elements.