Experts can think for us. If they say it was from groups of slaves with no tools or means to build such a tunnel, that was never mentioned in all the historical records, then like wooden doors on a gas chamber, it makes expert sense and you don't get to question
Experts can think for us. If they say it was from groups of slaves with no tools or means to build such a tunnel, that was never mentioned in all the historical records, then like wooden doors on a gas chamber, it makes expert sense and you don't get to question