Rescue workers work on the damaged section of the Pentagon following the 9/11 terrorist attack.

As a World Trade Center tower collapses behind them, people flee on Sept. 11, 2001. Within weeks, the U.S. was at war. The next 10 years saw the Pentagon triple contracts awarded without competition, to $140 billion.

U.S. Marines leave the Kandahar Airport in Afghanistan On New Years' Eve, 2001. In the ensuing 10 years, much has changed about the military's fighting tactics as well as the weapons needed to fight it, creating a bonanza for defense contractors.

Former Secretary of Defense Donald Rumsfeld awards purple hearts and medals at Camp Liberty in Baghdad. In its rush to war, and in the decade afterward, the Pentagon awarded billion-dollar contracts with no competition. 

A U.S. Army soldier has a coffee between missions in Iraq. Houston-based contractor KBR has built elaborate facilities in Iraq and Afghanistan with no-bid contracts that top $37 billion after 10 years of war.

The Pentagon turned to Russia to buy Mi-17 helicopters, like these shown here, to equip the Afghan and Iraqi militaries, to the consternation of American companies.

The Pentagon tried to sole-source a new line of refueling tankers to Boeing for $37 billion, citing the urgency of war, but was overruled. Even though Boeing eventually won the contract, a competition with Europe's EADS forced down the cost of the contract and saved taxpayer dollars. 

More than 6,000 Americans have died in Iraq and Afghanistan. The Pentagon has spent billions of dollars on weaponry to better protect soldiers at war.

Secretary of Defense Donald Rumsfeld talks with troops in Iraq. KBR has been paid $37 billion to build infrastructure like this dining hall.