The Gate of Nature is located in Qing'ao Bay on the eastern end of Nan'ao Island. It is the 11th Tropic of Cancer Tower built by China. It plays an important role in the study of the world astronomy and geography. When the sun shines directly on the Tropic of Cancer, the shadow will pass through the center of the upper ball and project into the center of the platform, which is one of the new attractions in South Australia. The construction of the logo of the Tropic of Cancer in the Tseung Kwan O Bay has added a new member to the Tropic of Cancer logo family. It is also another measure for human beings to better understand the Tropic of Cancer and to understand the Earth.