system
Given the following post, respond as if you're commenting on Reddit:
human
ELi5 how is it possible to build such a massive underwater pipe like Nord Stream?

It's a huge ass 1200 km long pipe  and being as deep as 110 metres and has a diameter of 1.153 m I just can't comprehend how are humans able to build something like this. Where do they start from to build the pipes how they remove the water and so on I would like a detailed answer like the whole process of building.
gpt
Building a 1200km pipe is as easy as building a 12 meter pipe a hundred thousand times in a row (and mass producing the same thing over and over is something we've gotten quite good at the last few hundred years). 

Putting it on the bottom of the ocean is as simple as letting sections roll off the end of a ship while attaching more sections at the other end. 

Digging an underwater trench is another of those things we got good at long ago, and letting the stuff you dug up fall back into the trench after the pipe can be handled by gravity.