Assuming ancient levels of technology, perhaps 2500-1500 BC, how would one be able to make a underground city like that of Kaymaklı, while having it be able to be breathed in and, is possible, have a basic water system? I am aware that at least the breathing is possible, but not fully aware how it is so.
Also, how are these kept from collapsing when mining larger chambers? Larger Chambers as in around 4.6m x 5.5m to a little above. This spreads into various different groups of rooms branching off one another, and various tunnels as well. This would be separated into general storeys, perhaps around 15-20, going upwards and downwards in the mountains, total that is, not 15-20 in both directions.
In a real-world analogue, one could compare it to just being built into mountains. Mostly the lower ends of them, and not near the peaks. Sort of like the Andes in terms of the vast rainforests on one side, and very dry deserts on the other, very typical for mountains, I know, but this is just the kind of mountains I thought of when conceptualizing the city.
Would be preferable if sources of how this was done are cited, and if possible, linked to. Thank you.