Gate of Nature

The Tropic of Cancer Monument "Gate of Nature" of Nan'ao stands on the Tropic of Cancer Square at Qing'ao Bay, Nan'ao County. It is the 11th Tropic of Cancer monument constructed in China to date.

Its architectural shape is derived from the Chinese character "Men" (Gate). The sphere has a radius of 3.21 metres, corresponding to the Spring Equinox on March 21; each cantilever stretches 6.22 metres, matching the Summer Solstice on June 22; the total height from the base to the sphere is 12.22 metres, corresponding to the Winter Solstice on December 22. The tilt angle of the two gate pillars precisely aligns with 23.50 degrees North Latitude. At noon on the Summer Solstice every year, when the sun shines directly on the Tropic of Cancer, sunlight will pass through the circular tube at the centre of the upper sphere and cast a shadow onto the middle of the platform.

"Gate of Nature" is located at Qing'ao Bay on the eastern tip of Nan'ao Island. Covering an area of 33 mu, the Tropic of Cancer Square was donated and built by Shantou Zhonghuan Investment Co., Ltd. Adjacent to Zhonghuan Blue Sea & Blue Sky Holiday Community, it integrates seamlessly with Haiyue Top Resort Hotel, Haiyue Villas, Haiyue Apartments and a characteristic commercial street. It remains the 11th Tropic of Cancer monument built nationwide. According to its designer Zheng Shaowen, the monument’s silhouette evolves from the Chinese character "Men". Its dimensional figures carry symbolic dates: a 3.21-metre sphere radius for the Spring Equinox, 6.22-metre cantilevers for the Summer Solstice, and a 12.22-metre height from base to sphere for the Winter Solstice. The slant of the two pillars exactly equals 23.50°N. Each summer solstice noon, direct sunlight penetrates the central tube of the sphere and lands at the platform’s centre. Together with the Tropic of Cancer monument on Chicken Cage Mountain in western Shantou, Nan'ao’s "Gate of Nature" forms a distinctive complementary landscape — one by the sea and one on a mountain, echoing each other from east to west.

Crossing the much-anticipated Nan'ao Bridge, visitors will encounter an unmissable landmark, the "South Gate of the Motherland": the Tropic of Cancer Monument. The Tropic of Cancer marks the northernmost latitude where the sun can reach vertical overhead insolation in the Northern Hemisphere, sitting at 23°26′21.448″ North Latitude. It is the northern boundary of vertical solar radiation on Earth. The area receives direct overhead sunlight around June 22 every year, the Summer Solstice.

As Shantou’s second landmark building, the construction of the Tropic of Cancer marker at Qing'ao Bay bears profound significance. China boasts a concentrated cluster of Tropic of Cancer landmarks scattered across regions including Chiayi and Hualien in Taiwan, Guangzhou and Fengkai in Guangdong, and Guiping in Guangxi. These unique landmarks along the Tropic of Cancer are exclusive to China and serve as vital research sites for astronomers and geographers worldwide. The completion of the Qing'ao Bay Tropic of Cancer monument adds a new member to the country’s collection of such markers, representing another milestone for humanity to deepen its understanding of the Tropic of Cancer and planet Earth.