Mass Observation was created in 1937.
Observation on the Spot was created in 1982.
Ground Observation Corps was created in 1950.
Observation Tower Burgholzhof was created in 1891.
Hünenburg Observation Tower was created in 1952.
Wanne Observation Tower was created in 1888.
Observation Tower Height of Goetzingen was created in 1883.
Sinnott Memorial Observation Station was created in 1931.
Hadley Mountain Fire Observation Station was created in 1917.
Prospect Point Park observation tower was created in 1961.
Blue Mountain Fire Observation Station was created in 1917.
Kane Mountain Fire Observation Station was created in 1925.
Combined Pilots-Observation Badge was created on 1936-03-26.