But then, running along the highest ridges of the mountains

 But then, running along the highest ridges of the mountains, you see it: The Great Wall – one of the great marvels of human history.In its entirety, the Great Wall stretches from east to west across more than 13,000 miles of Chinese countryside that's about four times the length of the entire United States from Maine to Oregon!.It is not a single, uninterrupted wall, but rather a series of smaller walls which sometimes overlap and run parallel to each other.Certain sections of the Wall date back as far as the seventh century B.C., but the majority of the Great Wall we know today including the section at Mutianyu was built between the 1300s and the 1600s.

To get to the Wall, we rode a cable car up a mountain and we later rode back down on a long slide.  The section we visited is one of the more popular parts of the Wall for tourists, and it's easy to see why.  At Mutianyu, the Wall is roughly 20 to 25 feet tall and full of stairs, and there's a watchtower every 100 yards or so. Those watchtowers serve as a reminder of why the Wall was built in the first place to defend against attacks from armies descending from the north. Throughout its history, the Great Wall has gone through decades, even centuries, of ruin and disrepair.  But it has always served as not only a physical barrier, but a psychological one to intimidate potential invaders.

During our visit to the Wall, I couldn't stop thinking about what a massive undertaking it must have been to build it. Hundreds of thousands of soldiers and peasants were given the dangerous, painstaking – and often fatal – task of carrying ton after ton of granite, brick, dirt, and wood through the forests, up over the hills, and down through the valleys to create this incredible structure. They did this year after year, decade after decade – and it's because of their hard work and sacrifice that the Great Wall remains standing today.During her trip to China, First Lady Michelle Obama said an odd thing to the children of that country who the government allowed to visit with her.During her visit to China, first lady Michelle Obama pointed out that the ability to travel outside of the United States was "rare" but that she chose China for a reason.