Shbikes, I am not certain if it is an international or a Belgian-Dutch cultural thing, but there are a lot (like in every small town!) of '4daysies' or '5daysies' or '6daymarches' being organized in the Netherlands during spring and summer, mostly take place on 4 evenings in a row (not exceeding 10 miles per evening usually) but others in nature (along the coastline) or for longer distances (originally military and mass-events, not my preference but that is the only link i could find in English, sorry International Four Days Marches Nijmegen - Wikipedia, the free encyclopedia). You also have long nightwalks (14 hours) or even 24hour walks.
I have truly no idea if this is also an American or English practice? Anyways, I suspect the topic opener is leading such kind of a local event, and the walking pace is over 3 to 4 miles per hour excluding rests, which would make an average of just over 2 miles per hour sound plausible. Usually, there is only one or two small (soup) breaks and a big meal at the end.
Sorry, I went a bit off topic, but i thought it to be a curious relict of military marches.
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