Long before the cyclops at the end of the Spongebob movie made deep sea diving popular, there was a long and fascinating history to it, involving people who are just as famous as the yellow sponge.

The first records of deep sea diving come from the ancient Islamic world, whose people created glass diving bells they’d lower from ships. There are a few paintings depicting when Alexander the Great hopped in one of these and checked out the seas around the lands he had just conquered.

After that, the next great innovation came from Leonardo Da Vinci, who designed a deep sea suit. His wasn’t for ocean research like most of them, but actually for military purposes. He devised a suit made out of leather that was meant for stealth missions in Renaissance sea battles, which is the coolest thing, maybe ever. His sketches of the suit survived, and people even made a few (terrifying) prototypes.

Then by the 1700s, a French aristocrat made a diving suit, but they wouldn’t start to resemble the awesome steampunk, alien knight hybrids we’re most familiar with until the mid-1800s. 

Once they developed the iron suits with atmospheric windows and weighted shoes, they finally became produced on a larger scale, giving us some of the coolest photos known to man and fish alike.