“Caesar set his legion’s All Day speed at exactly “twenty Roman miles in five summer hours,” or 15:00 minutes a mile. The next faster gear was double-time, a 13:30 clip that covered twenty-two Roman miles in five hours. When you factor in the gnarly terrain and 45-pound packs on their backs, that’s a churn rate any ultrarunner would envy.”

“Caesar set his legion’s All Day speed at exactly “twenty Roman miles in five summer hours,” or 15:00 minutes a mile. The next faster gear was double-time, a 13:30 clip that covered twenty-two Roman miles in five hours. When you factor in the gnarly terrain and 45-pound packs on their backs, that’s a churn rate any ultrarunner would envy.”

— Christopher McDougall