Asked by Khalid Waters Leaning Tower of PisaArchitectureItaly
Why doesn't the Leaning Tower of Pisa fall over?
January 03, 2020 8:56PM
The tower hasn’t hit the ground yet because its tapered and slightly curved shape keeps its center of gravity fairly low. That means it can tip quite a bit before toppling.
In a more poetic sense, though, the tower was falling over for a long time—albeit very slowly. Its tilt, which was first noticed shortly after construction began in 1173, kept increasing until 1990. That’s when engineers declared that, at a tilt of more than five degrees, it was in danger of collapsing. A team then figured out how to correct the lean, bringing it back to a safe angle.
Since then, it’s been getting straighter, believe it or not. The residual effects from the construction meant the angle had decreased another four centimeters by 2018.