Obamas climb Great Wall after lunch of trout

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.

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