The Great Wall of China is one of the longest manmade structures in the world. Stretching more than 13,000 miles and dating back thousands of years, the ancient marvel in today"s picture is a series of fortifications spanning rugged mountains, valleys and deserts. Featuring steep trenches and watchtowers, parts of it were designed to keep invaders at bay. Hiking this UNESCO World Heritage Site offers a unique glimpse into this historical landmark. The experience varies from well-preserved sections like Mutianyu to wild, unrestored parts such as Jiankou. Some steps are so high, they"re more like steps on a ladder! The Great Wall of China isn"t just a wall, but a symbol of perseverance and strength.