The pagoda underwent a thorough renovation in the 1980s, with steel rods used to stabilize the structure. But as it continues to shift, authorities are taking new steps to protect it. [Photo/CNTV]

Located on Tianmashan in Songjiang district, the Huzhu Pagoda has shifted slightly over the past few decades - but not enough to spot easily with the naked eye.

Data this year suggests the pagoda is now leaning at an angle of 7.1 degrees. But in 1982, the tilt was about 6.5 degrees - much larger than the four-degree tilt of the Tower of Pisa.

Visitors are now kept at least two meters from the pagoda.

"We saw the pagoda from far away and were very curious about it. When we stood under it, we felt terrified as if it was falling down," said a visitor named Tu Fanghua.

The tower was built in 1079 during the Song Dynasty, and was originally part of a complex used to store Buddhist relics. But the rest of the complex was destroyed in a series of fires.

The pagoda gradually tilted over the years, as it was located on a slope, with one side of the ground being softer than the other. And it has a large hole on one side of its foundation, which was caused by nearby residents digging for treasure in the area during the 1940s. But experts say the structure is currently safe.