[AlotOfReading]

They were not. The primary stonework technique was almost certainly pecking [1], where you take a small "hammer" and whack it against the stone, pulverizing a bit at a time. This leaves a characteristic surface you can observe on the pillars today. However, the Gobekli Tepe builders were a bit smarter than just carving everything from scratch. They made use of the exposed limestone layers to quarry materials that were roughly the right shape and thickness.

[1] https://stonetoolsmuseum.com/technique/pecking/

[sigg3]

People who shout about ancient aliens and hidden technology always completely ignore that the people in the past had access to the most advanced machinery available: humans.

Add time to that, so that your project can have a scope of generations, passing down knowledge gained from a lifetime of doing this particular thing, the results become unsurprising even.

Amazing, inspiring and ingenious but also unsurprising.

[fsloth]

Yeah, human craftmanship can reach really, really complex heights.

I guess industrialization has made lot of people oblivious to this fact.