Keywords: aviation military aviation militaryaviation observation balloon observationballoon lighter than air lighterthanair lta the great war thegreatwar great war greatwar world war i worldwari world war one worldwarone the first world war thefirstworldwar wwi ww1 View of a military aerial observation balloon being held just off the ground by its mooring ropes by a group of unidentified soldiers during World War I (undated) [Photograph taken or collected by Henry L. Graves]. --From Henry L. Graves Papers, WWI 55, Military Collection, State Archives of North Carolina View of a military aerial observation balloon being held just off the ground by its mooring ropes by a group of unidentified soldiers during World War I (undated) [Photograph taken or collected by Henry L. Graves]. --From Henry L. Graves Papers, WWI 55, Military Collection, State Archives of North Carolina |