The Great Wall of China was built over several centuries to protect the historical northern borders of China from raids and invasions from nomadic group from the Eurasian Steppe. The earliest sections were built all the way back in the 5th Century BCE during the Warring States period, although little of this still remains.
The most famous and enduring sections of the Great Wall are the stone wall stretches in the northeast that were built during the Ming Dynasty (1368-1644 CE) - these are the iconic sections that snake over the mountains in a phenomenal feat of engineering. All in all, Ming walls measure a staggering 8,850 km long in total.
The Jinshanling section of the Great Wall is one of the most spectacular sections along the whole length, located in a beautiful mountainous area northeast of Beijing - it is over 10kms long, crosses 5 mountains passes, and contains 70 towers. Built from 1570 CE during the Ming Dynasty, some sections have been expertly restored to their original condition, while other parts are left in a natural eroded state as they approach Simatai (another famous section of the Wall to the east). It is an incredible place to explore on foot.