Why it matters
About two dozen vast man-made caverns with uniform chisel marks; Han pottery dates them past 2,000 years. The only real open question is their purpose.
What mainstream says
Unambiguously man-made and dated; the no-tools framing is a viral myth.
Graded Grounded · A on the Ancient Code honesty scale (A grounded · C contested · S speculation · U unidentified). It belongs to the Impossible stone line of evidence.
Sources & further reading
The authoritative reference for this site/finding — and its own primary citations — so you can check us.