Early emperors had built walls in the northern territories to protect their nation against attack from outside forces. These walls were spread across the landscape and not connected. Qin was an ambitious leader. He ordered his people to connect the existing walls together, and to expand them, eventually covering a distance of over 4000 miles (6437km), as seen in this map.
Over 300,000 peasants were forced to help build the Great Wall of China. Many of which died during the construction. After working for several years, the Great Wall of China was completed and still stands today as one of the great building projects in human history.
Pay attention to your enemies, for they are the first to discover you mistakes.
In the winter of 1848, a large chunk of ice blocked Niagara Falls for 30 minutes. This is the only time that the waterfall is known to have stopped flowing.