9 April in history.

1959

The Mercury Seven. NASA introduced its first seven astronauts. They became national heroes and paved the way for Americans in space.

Wikipedia: Mercury Seven

Photo: NASA on The Commons / Wikimedia Commons (Public domain)

More from 9 April

1. 

   1860

   The oldest known recording of a voice

   Édouard-Léon Scott de Martinville recorded someone singing "Au clair de la lune" as squiggles on paper. Scientists played it back for the first time in 2008.

   Wikipedia: PhonautographWikipedia: Édouard-Léon Scott de Martinville

   Photo: Édouard-Léon Scott de Martinville (1817–1879) / Wikimedia Commons (Public domain)

2. 

   1947

   The Journey of Reconciliation

   Black and white men rode buses together through the American South to test a ruling against segregated travel. It inspired the Freedom Rides of 1961.

   Wikipedia: Journey of Reconciliation

   Photo: Amyjoy001 / Wikimedia Commons (CC BY-SA 4.0)

3. 

   1967

   The Boeing 737 first flies

   The small twin-engine jet made its first flight. It became the best-selling passenger jet in history.

   Wikipedia: Boeing 737

   Photo: mr_t_77 / Wikimedia Commons (CC BY-SA 2.0)

4. 

   1969

   Britain's Concorde takes off

   The first British-built Concorde made its first flight, from Filton near Bristol.

   Wikipedia: Concorde

   Photo: Arpingstone at English Wikipedia / Wikimedia Commons (Public domain)

Moments chosen for discovery, creativity and courage. Each one links to a source where you can read more; photos are credited to their owners.