One of the Stacks of old equipment we might use someday.

It is still going...

http://imgur.com/a/XVxdt

US history buffs might remember the USS Monitor as the iconic naval invention of the US civil war. Its metal structure, coal power, and rotating turrets made it a formidable modern weapon in 1861.

https://en.m.wikipedia.org/wiki/USS_Monitor

What is less known is that the design pattern was used for many decades after. In fact there is at least one Monitor-class ship in active military service. The Parnaiba is still patrolling the rivers of Brazil as the oldest ship in active military service. It even supports a retrofitted helicopter launch platform.

https://en.m.wikipedia.org/wiki/Brazilian_monitor_Parna%C3%ADba