The Roman soldiers were known to be perfectly drilled.
This was made possible due to the extreme fitness and strength that they inculcated. This can be gauged from the fact that they could march for more than 20 miles a day. Moreover, they were able to undertake such treks even when they were wearing full armors and carrying heavy weaponry and equipment such as shields and swords.
Here are some of the most dangerous and insane bridges in the world that you'll have to think twice before crossing. Some of them are just breathtaking...