National Museum of the U.S. Air Force

"Leonardo da Vinci Machines in Motion" is on tour from Florence, Italy. It lets visitors explore 40 full-size working machines designed by scientists and artisans using methods from da Vinci's time.

The Boeing 707 that carried assassinated President John F. Kennedy's body from Dallas to Washington, D.C., is center stage in a new $40 million hangar at the U.S. Air Force Museum in Dayton, Ohio.