periscope

In a test a year before, he’d launched a torpedo with a nuclear warhead and watched the fiery explosion through a periscope.

Horne quotes contemporaries calling the headquarters “a submarine without a periscope”: a huge blunder when facing the Wehrmacht's speedy, flexible operational plans.

The Normandie crew spotted its periscope poking through the waves and sprang into action.

You can sit at the controls and peer through periscopes in a submarine room removed from attack submarine USS Greenling.

In the pond at Manito Park, a moose waded in small circles, standing neck-deep in the murky water, head poking out like a periscope.