I was recently in New Grange (goole it)
It is solar aligned and the dry stack has been standing for thousands for years. The inside is still bone dry so if you get it to exist it will likely exist for human scale forever
When ya get to the big stuff, 1,000 pounds up. Just add me to the resource list. Built many adventure golfs on the "hill" caves, retaining walls and waterfalls. Natural stone not gunite. Up to 12 ton, (bout the size of a vw beetle).