When Will the Leaning Tower of Pisa Fall Over? Photograph of the
Leaning Tower of Pisa taken circa 1890-1900. CREDIT: Library of
Congress Experts say the famous tower at Pisa will lean for at
least another 200 years. It may even stay upright well, almost
upright forever. That's all thanks to a restoration project,
which brought the tower back from the brink of collapse a decade
ago. From the first moment of its construction on unstable
subsurface soils in 1173, Pisa's bell tower tilted farther and
farther to the south. Its early-onset lean even influenced the
way it was built, as its architects tried to compensate by
angling the structure northward, resulting in its being banana-
shaped. A few ill-advised construction projects accelerated the
Leaning Tower's invisibly slow fall during the past couple of
centuries; it tilted 5.5 degrees, its acutest angle ever, in
1990. By all calculations, the tower should have toppled at just
5.44 degrees, but fortunately it defied the predictions of
computer models just long