I got the rare opportunity to tour the DSME (Daewoo Shipbuilding & Marine Engineering) yard in Okpo Bay, Geoje-Do South Korea a few years ago. I think it's the second largest shipyard in the world. It was really an unbelievable experience. Container ships are huge when they're in the water, but they're absolutely mind bogglingly immense in drydock, where individual sections dwarf most apartment buildings.
The range of ships they produce there is also rather mindblowing, in my tour I saw (in various stages of assembly) container ships, LPG transport vessels, crude oil ships, various navy ships and a handful of submarines among others.
The engineering going on is also fairly cutting edge. Problems like accurately predicting weld strength are still unsolved and they had a large computational modelling R&D programs I got a glimpse of while I was there.
If you squinted a bit, it almost felt like huge starships were being assembled there.
https://www.google.com/maps/@34.8706117,128.706339,6867m/dat...
Down the street (more or less), in Gohyeon, is another huge shipyard which I think Samsung Heavy Industries runs.