The Leaning Tower of Pisa is a world-renowned piece of architecture due to its fascinating incline. However, in China’s central Henan provinces, a rare set of twin towers in the local Shousheng Temple have also been defying gravity for centuries.

The taller one of the twin towers, which is 30 meters tall, tilts 40 centimeters toward the northeast. The other four-story tower is 18 meters tall. Both towers are hexagon architectures without roofs.

According to Ran Xiaoshui, the 80-year-old tower watcher, started in Tang Dynasty (618~907 A.D.), the construction of the twin towers was halted during the early Song Dynasty (960~1279 A.D.) due to invasions, and hence the structure has remained roofless.

“In 1986, after conducting a vertical measurement, local heritage bureau found that the top center of the tower leans 40 centimeters away from the bottom center. In the same year, the twin towers were registered as a heritage protection site by the provincial government,” said Ran.

Chang Tiewei, an expert on ancient architecture explained that the incline of towers may be caused by the bearing capacity of the foundation or underground water flow.

“During maintenance of the twin towers in 1980s, we noticed the incline. Since the towers are built right on top of the alluvial fan of the Yellow River, which is mostly made up of sandy soil, it may have triggered the leaning angle,” said Chang.

Chang added that to straighten a tilted tower is a global challenge. The Leaning Tower of Pisa was recovered by elite experts from all across the world.

“The recovery for the twin tower is no easy task. Currently the tower is not on the edge of collapse and its underground structure is more stable than before. A long-term observation is necessary before actually getting into plan formulation,” Chang noted.