A black and white photo of a WW1 era aircraft listening station. Basically two cones, several meters in length and something like a meter and a half in diameter at the wide end, mounted on a stand and angled slightly upwards. A man is standing behind and below them, with a flexible tube going from the narrow end of each of the cones to a corresponding earpiece, so that he can hear the sounds being picked up in stereo.

Sorry, no caption provided by author