‘Observation’ historical pictures (exact matches)

Observation balloon ascending, World War I
Observation balloon ascending, World War I
Discovering Our Cities: The Marvel of the Mersey (Liverpool). Jeremiah Horrocks.
Discovering Our Cities: The Marvel of the Mersey (Liverpool). Jeremiah Horrocks.
In 1911, Lt Giulip Gavotti became the first man to drop a bomb from a plane
In 1911, Lt Giulip Gavotti became the first man to drop a bomb from a plane
Il Presidente della Repubblica Francese alla fronte italiana
Il Presidente della Repubblica Francese alla fronte italiana