Walking 25 km / day :
The distance that Muslim travelers used to travel in pre-industrialization days were 25 km daily. From which came the term "a days distance" or "1 manjil distance". Manjil here means camping for the day.
But how would it convert to modern times? When we have paved roads and don't walk on rough terrains like in the old days?
Yesterday there was a news of a walker in BD who traveled form north most point of BD to south most. He walked 1000 km in 31 days. He said he used to walk 30 km / day on average. Indicating that limit is almost still the same in modern times.
I was watching a documentary many years ago on an European or American walker. He said even though he used to walk longer distance in the early days, now his daily walk is 24 km. Exactly the same as the arab travelers.
The longest I believe I walked on a single go is when I used to return from Tongi field to home after the last day of gathering. That distance I measured on maps is 18 km.
And during Hajj if one decides to walk to Arafa on the hajj day, he has to walk 18 km too. It takes about 3 to 4 hours.