I confess, I don't know a lot about how theses pipelines are constructed or operate.

I understand they are about 4 feet in diameter, made of inches thick steel, and are cased in a few inches of concrete to hold them down.

It appears they are constructed in segments. I haven't found out how those segments are joined, Bolted, welded, both? Does this joining occur underwater or on a laying ship? Joins are weaknesses. So many questions. Along this pipeline, are there stations that act as relief valves if needed? Pressurization nodes? Pumps? Monitoring stations? This stuff connected to the internet, by any chance? But don't forget that the Russians suck at infrastructure. Did we ever find out what that huge explosion was in the north a few years back?

Rumors of Russian ships and subs in the area.

So how, exactly, would one blow up an undersea pipeline? Me thinks it would take a lot of resources. Or a lot of cleverness.