Gotha G.IV Bomber and Sopwith Camel WWI Aircraft Aviation Art Print by Artist Stephen Chard GAvA

Replacing the Zeppelins that had proven so costly and vulnerable to operate over England, the German Air Service introduced what many believe to be the first strategic bombers, the Gotha bombers.

Often mistaken for being one type of aircraft, the Gotha bombers were actually produced in several versions from as early as 1916 but it was the Gotha G.IV, seen here,  that was the first truly effective aircraft, mounting their first raid on England in May 1917. 

By this time however there was a rudimentary Home Defence system in place and daylight raids proved too costly in both aircraft and crew. As a result operations were conducted by night from later in 1917.