Xu Xiake toured and investigated 16 provinces in his lifetime, covering almost the whole country. When he was carrying out his investigations, he never took blind belief in the conclusions in the books. Instead he found a lot of unreliable points in the geographic records taken by his predecessors. In order to make his investigations reliable and thorough, he seldom traveled by carriage or boat. Instead, he took long, arduous trips on foot almost all the time, climbing mountains and hills. In order to learn the truth of nature, he always chose to conduct investigations in mountainous roads and lonely woods, where he discovered a lot of magnificent peaks and beautiful sights.