The "Nature Gate" of the Tropic of Cancer sign tower in South Australia is located in the Tropic of Cancer square in Qing'ao Bay, Nan'ao County, Shantou City. It is said that every summer solstice noon, when the sun directly shoots the Tropic of Cancer, the sun will pass through the round ball center tube above the "Nature Gate" and project the center of the platform. Achieving the effect of "stand up poles do not see shadows", people are reflected, interesting.