The Iraqi air force, devastated by the Gulf War, had only 80 to 100 operational combat aircraft, according to Periscope.

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In the game Steel Diver the 3DS functions as a submarine periscope, with the screen displaying a view of enemy ships on the surface.

FORBES: Technology

The Royal Navy's official inquiry concluded HMS Affray sank because the snort mast, the tube through which the diesel engine "breathed" while the submarine was at periscope depth, snapped because of metal fatigue.

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"The Germans built the bunkers according to absolutely standard patterns, so we can walk into one and know straight away where everything will be - the hole for the radio mast, another for the periscope, the air vents, the sleeping area and so on, " said amateur archaeologist Jean-Francois Laquieze.

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