The present wall, whose image is so well known, is not Shi Huangti's wall from c. 221 BCE. There is actually very little of the original wall left today. When the Qin Dynasty fell in 206 BCE, the country split into the civil war known as the Chou-Han Contention, fought between the generals Xiang-Yu of Chou and Liu-Bang of Han, the two leaders who had emerged as the most powerful of those who had helped topple the Qin Dynasty. When Liu-Bang defeated Xiang-Yu in 202 BCE at the Battle of Gaixia, he became the First Emperor of the Han Dynasty and continued construction of the wall as a means of defense. He was also the first emperor to use the wall as a means of regulating trade along the Silk Routes (better known as The Silk Road) from Europe to China. The following dynasties all made their own contributions and repairs to the wall until the Ming Dynasty (1368-1664 CE) initiated a massive building project to protect the country from invading nomads from Mongolia, the very same incentive that had played a part in Shi Huangti's original vision. This similarity in purpose may explain the belief that the present wall dates from the Qin Dynasty. The Ming built the wall featuring over 25,000 massive watchtowers and ranging in height from 16-26 feet (5-8 meters), 20 feet across the bottom (6 meters) and 16 feet across the top (5 meters).