This is something historians still puzzle about, what with current reports that China is building a "blue water" capability to project power far beyond its own shoreline.

CNN: Building On A Golden Age

When their 3-meters long robot, nicknamed "Anna Konda", is connected to a fire hose the hydraulics enable it to project a powerful stream of water and give it enough power to lift 650 kilograms, strong enough, its developers believe, to punch a hole through a door or wall to get to the flames.

CNN: Snake robots slither to the rescue

The project, at an old water mill at Neen Sollars, Shropshire hopes to generate power for 10 homes by May.

BBC: Shropshire