This appears to be somewhat of a naturally-occurring yakhchal: https://en.wikipedia.org/wiki/Yakhchāl https://en.wikipedia.org/wiki/Yakhchāl Something I've alw

This appears to be somewhat of a naturally-occurring yakhchal: https://en.wikipedia.org/wiki/Yakhchāl https://en.wikipedia.org/wiki/Yakhchāl Something I've always rated quite highly as far as ingenuity goes.