I've enjoyed hiking and walking all of my life. One of my most memorable treks was hiking the Inca Trail in Peru. Hard to believe it's been 25 years since my brother and I did that walk, and I'm glad I did it then because my worn knees would not be up to the task today.
The hike lasted four days and wound its way up and down and across the Andes, starting in a desert climate and ending in a cloud forest. Our highest altitude was 4200 m (13,800 ft), a level at which it's quite cool even when so close to the equator.
One of the photos from our hike (below) was used in last weekends One Clue Mystery, wherein the stony trail seems to lead you up to the clouds (although that's an optical illusion as it is actuality a descent down a hill). Congratulations to George G, who recognized where we were.
The trail is steep throughout and hard work as the pitch is so steep it would make a modern trail-builder shudder. When you look carefully at the photos below, you'll see the linear trail outline as it works itself up the Andes.
What I was surprised to find out is that it is not until the 3rd day, after you summit Dead Woman's Pass, that you actually begin to walk on the original Inca Trail -- the stone trail laid hundreds of years ago. Until that point the trail was mostly dirt and more like a usual mountain walkway.
The Incas had actually created an extensive road network for foot traffic through the mountains, of which this is a small part. Much of the rest has been overgrown or lost through landslides and such.
While the original trail is quite rough, it's a wonder to behold. It's a pedestrian highway created by millions of hand-placed rocks designed to create sure-footing and a clear path to speed the movement of Inca warriors through the Andes. The trail is wide enough for several soldiers abreast to move in formation through the mountains.
One of the fascinating aspects of the trek is that you often spot old Inca ruins along your journey. For example, the Tambo (old Inca military structure) Runkuraqay is shown below:
Of course, camping along the way and approaching Machu Picchu from the Sun Gate on the last day are amazing memories, but those are stories for another day.