Barack Obama's inauguration also marks the official debut of an "ugly-looking" new presidential limousine, a cross between a Cadillac and a hardened missile silo, a gizmo that James Bond would probably envy.
The new Cadillac model of the presidential limousine was made by General Motors Corp and unlike other presidential limo models it does not have an official model name. By some accounts, it is called "The Beast."
Judging by its approximate weight (6349 to 7256 kilograms) and wheelbase, the fuel guzzler rides on a modified medium-truck GM chassis.
While the engine size and type of Cadillac has not been revealed, the limousine is thought to be equipped with "run-flat" tyres, 5-inch thick armoured plating, bullet-proof windows and a chassis sealed to protect against chemical or biological attack. The Secret Service has not revealed its cost.
In comparison with previous generations of presidential limos, Obama's car is seriously ugly, a brute, charmless rectangle of steel and glass that less conveys the grandeur of the office than the withering paranoia of the age, US media reports said.
"If the sleek, knife-sided elegance of Richard Nixon's Lehmann-Peterson Lincoln Continental can be compared with the Greek-inspired columns of the Capitol, the new limo is a Bethesda parking garage," Los Angeles Times commented.
Some time after September 11, 2001, the Secret Service has adopted a policy to destroy presidential limos after they are taken out of service in order to protect their secrets. It's become routine to replace the presidential limo every four years at the beginning of a new term, media reports said.