What are the most complicated machines humans have built?
I'm researching for a blog post on humanity's most complex machines.
JWST, EUV lithography, and LHC come to mind.
What other engineering marvels should I look into?
Look into the changes wrought by Henry Maudslay. He changed the world from one where a single threaded screw took a week's work by an apprentice, to one where you could make them with a lathe. He changed the best tolerance from a 10th of an inch to a 10,000th of an inch. He's best known for the first practical screw cutting lathe.
Also see the 3 plate method of Whitworth, who made it possible to make accurate flat surfaces.
Also see the work of Carl Edvard Johansson, the Gage Block system. Without it, Ford couldn't have mass produced the Model T, and life would be completely different.
Our social machines. A judiciary, political, health, social system which works relatively smoothly
I think electricity grids are very very impressive. Even the US' which is considered out of date works in that it spreads across the entire country, needs to meet demand and supply down to milliseconds, has do many points that withdraw power and points that add power to the grid. Crazy stuff
One thing that keeps on giving for me me is being able to watch some random youtube video like its nothing. I can click on a random 200 view video from 12 years ago and scrub through it basically no latency. Thinking about how every little packet goes up and down the stack and around the world... The whole infrastructure to make it so seamless.
Meanwhile watching a video from an external drive or my wired SMB NAS fails half the time :|
I've often seen the space shuttle get tossed in when discussing complex achievements.
There was also a cold war era icbm ins with over 15000 parts with accuracy within a few hundred meters anywhere on the globe. Can't remember the exact model number.
For a certain definition of complicated, I would say atomic clocks.