Caisson lock

That looks properly terrifying.

The May 1799 test, above, occurred when a party of investors was aboard the vessel and they nearly suffocated before they could be freed. Work on the second lock was suspended

One of my favourite YouTubers Paul Whitewick did an interesting video on this.

Way to get rid of the capitalists. A bit tortuous but very original.

Yeah, no. Thanks, but not at all.

I don’t get claustrophobic or anything, but just looking at that made it clear that that wasn’t a place I’d ever wish to be