"Important Landmarks of Nan'ao Island" The "Nature Gate" of the Tropic of Cancer sign tower on Nan'ao Island is the 11th Tropic of Cancer sign tower built in Qing'ao Bay Tropic of Cancer square. It is at the intersection of the Tropic of Cancer and the eastern shore of China's mainland. The only Tropic of Cancer sign tower located on the island. The tower design uses the Chinese character "door" for evolution, the radius of the sphere 3.21 meters (corresponding to the spring equinox on March 21), the cantilever length 6.22 meters (corresponding to the summer solstice on June 22), from the base to the height of the sphere 12.22 meters (corresponding to the winter solstice on December 22), The angle of the gateposts on both sides corresponds to the north latitude. Every summer at noon, when the sun directly shoots the Tropic of Cancer, the shadow will pass through the center of the ball above the circle and project the center of the platform. The "Nature Gate" of South Australia forms a mountain, a sea and an echo of the symbol tower on Jilong Mountain in the western suburbs of Shantou. The "Nature Gate" Tropic of Cancer sign tower has become an important landmark in South Australia. It should be a must-check place for every tourist on Nan'ao Island!