Answer: I believe it is often said that "Hiking up a mountain in the southwestern United States is like walking from Mexico to Canada" because hiking up a mountain takes a lot more effort as to hiking down. If you have ever climbed up a lot of stairs at one time or climbed a steep or tall hill, you will notice the journey is much easier going down than up. That sentence is like a similie, where it is comparing hiking up a mountain to walking from Mexico to Canada.
