I have recently stumbled across this video on Youtube, where quite a magnificient building is carved into the soil with simple tools like a shovel and hoe. The location is somewhere in South America, according to the channel description.
The rock seems to be (easily) workable, but also stable enough to maintain smooth surfaces and carved shapes.
What kind of soil/rock is this?
Edit: There is no need to watch the whole video. The reference image pretty much sums up what is going on, and what's the basis of my question respectively, at least in my opinion.
Edit 2: As John pointed out in the comments, at one point the soil is mixed with water to make a clay plaster.