"Helicopter's first public flight on Dec 18, 1992"

Credit - US Air Force Museum

Helicopter was built by Oehmichen

Credit - Hiller Aviation Museum

Oemichen's first attempt at vertical flight.

Credit - Hiller Aviation Museum

Bothezat's helicopter with six-bladed rotors

Credit - Library of Congress

Helicopter for observation.

Credit - Hiller Aviation Museum

First helicopter to liftoff with a pilot.

Credit - Hiller Aviation Museum

Pescara built several helicopters

Credit - Hiller Aviation Museum

Cornu's helicopter with counter-rotating rotors

Credit - Hiller Aviation Museum

The Berliner 1921 single-wing

Credit - Courtesy of Aerofiles

Helicopter lifted its own weight

Credit - Hiller Aviation Museum

Helicopter built by J.C.H. Ellehammer.

Credit - Hiller Aviation Museum

Emile Berliner

Credit - Library of Congress

Cornu in his first helicopter.

Credit - ") 2001 Smithsonian Institution, National Air and Space Museum, Videodisc. 2B 5847"