President Obama moves in to shake the prosthetic hand of Army Sgt. 1st Class Leroy Petry while receiving the Medal of Honor. Petry lost his hand while tossing aside an enemy grenade to save his fellow soldiers in Afghanistan. "It says a lot about heroism and about the human cost of war," says Newseum senior manager of exhibit development Patty Rhule. "You pause and when you realize what it's about it sort of takes you back emotionally."