The only visible evidence of the ambitious tower he had planned is a cylindrical 76-foot-deep foundation hole and a ramp access to nearby Lake Shore Drive.
"Part of this is going to be paid for by the taxpayer--the hole is just too deep, " says Kenneth Rogoff, an economics professor at Harvard who specializes in financial crises.
While manned exploration had until now seen a 52-year hiatus, scientists have used two robotic unmanned vehicles to explore the Mariana Trench: Japan's Kaiko made a dive there in 1995 and the US-based Woods Hole Oceanographic Institution's vessel Nereus explored the deep in 2008.
Earlier, authorities warned that the massive hole under Bush's bedroom -- about 20 feet wide and 50 to 60 feet deep -- was still expanding, and the suburban Tampa house could collapse at any time.