When I heard about this previously I wondered if it's a way of developing tunnel boring technology and expertise that would ultimately be useful on Mars. Underground tunnels and spaces are likely to be useful for a Mars colony and Musk is trying to figure out a way to get someone to fund it here first.
"No diaspora of English nobility, many of whom left rather than become subject to Normans" - do you have any other links or more information about this comment, i.e. which nobles and where did they go? I'm curious to find out more as was not aware of this aspect. Thanks