Okay, um. I have ideas for the supports of an underground city for a fictional universe, but I have no idea which to use.

City details- the city is hundreds of feet underground, and was created by dragons carving it out over multiple generations. These dragons are blind and originally lived in cramped tunnels, but since the meeting up with a more advanced and knowledgeable species they were able to build the city and gain trade and communications with the outside world. The city is a metropolis underneath the world, concealed in vast caverns with hundreds to thousands of dragon residents, which range from the size of fae dragons to towering creatures three times the size of a full grown human.

This one (1)

This one (2)

Or this one (3)

I will keep tally below

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