This Photo Of The Day takes place at night, somewhere in Switzerland. The country is landlocked, so we can assume that they spend more on their army and airforce than their navy. I’m not sure which kind of anti-aircraft guns are used in these pictures, but perhaps the Oerlikon GDF, Oerlikon 35 mm twin cannons? Or do you have a better idea? Oerlikon is now part of Rheinmetall Air Defence AG.
Apart from how cool the tracers look at night, I’m pretty sure the noise from the cannons adds to the wonderful and unique sensation.
Caption, auto-translated from Schweizer Armee (Swiss Army):
“Star Wars” in Graubünden! The best fire unit of the medium anti-aircraft department 45 was allowed to fire two live series with tracer ammunition into the night sky. In addition to the popular night shooting, the unit trained in normal shooting during their refresher course in the Engadine.
The Oerlikon 35 mm twin cannon is a towed anti-aircraft gun.
Picture source: Schweizer Armee (Swiss Army)