In 1908, American geographer and explorer W.E. Geil came to China to study the Great Wall. He traveled on a mule, crossing several provinces, from Shanhaiguan Pass to Jiayuguan Pass, becoming the first person to complete a full survey of the Great Wall. In 1909, he published The Great Wall of China, which included over a hundred photographs of the Great Wall from various locations. Geil's team experienced the most challenging day of their entire journey surveying the Great Wall. Starting from Lianhuachi at an altitude of 297 meters, they climbed up to Jia'erling at an altitude of 1004 meters, with a vertical difference of 707 meters. This section of the route had no human settlements, making it extremely challenging for both Geil's team a hundred years ago and modern-day climbers. On that day, they not only took multiple photographs of the Great Wall but also had the team's artist, F. Jennes, create an accurate watercolor sketch. Let’s see the pictures below!