William Edgar Geil (1865-1925), a famous American traveler in the early 20th century, was a member of the Royal Geographical Society. He walked alone through the Great Wall in 1907-1908, and published "The Great Wall of China" in 1909, published by Sturgis and Walton Publishing House in New York, which is the first monograph on Great Wall in the world.
At the foot of Simatai Great Wall, a hotel named after William Edgar commemorates his contribution to the protection of the Great Wall of China. "