The Leaning Tower of Pisa began construction in 1173 but experienced problems when the third floor was built on weak, unstable soil, causing the tower to lean. Construction halted for over a century as the soil settled. When work resumed in 1272, the architect built taller floors on the opposite side to compensate, resulting in the tower's curve. Modern anchoring with steel cables and weights has stabilized the tower, though it remains tilted at 5.5 degrees.

1. Engineering Failures:
The Leaning Tower of Pisa
By Logan Foster

2. History
• The Tower of Pisa began
construction in 1173.
• There’s been a great deal of
controversy over who the
actual architect behind the
tower, and nobody really
knows who masterminded it.
• The tower took 174 years to
complete.
• It’s said that Galileo dropped
two cannon balls of different
masses from the top of the
tower to test his theories about
gravity, but the only word on
this comes from his secretary,
so it may only be a myth.

3. Epic FAIL
• The major problems
began when the
construction of the third
floor of the tower began
in 1178.
• The original foundation
was only 3 meters
(roughly 10 feet) deep
and it was set in weak,
unstable soil, which
caused the tower to begin
leaning to one side.
• Construction was
immediately halted, for
fear that the tower would
fall.

4. The Solution
• For the next century or so, Italy
was involved in several wars
and the project was ignored,
which thankfully gave the soil
time to settle.
• Had this not happened, the
tower would have toppled for
certain.
• In 1272, construction was
resumed, under the architect
Giovanni di Simone. In the
hopes that he could
compensate for the tilt, he had
workers build the tower with
the floors taller on the side
opposite the tilt. As a result,
the tower is curved.

5. The Solution (pt. 2)
• Construction was halted again
in 1284.
• The bell-chamber was finally
added in 1372, almost two
centuries after construction
began. Eventually seven bells
were added, one for each note
on the musical scale, the last
installed in 1655.
• The tower is today anchored
with steel cables and lead
weights, which has rectified
the problem (for the most part.)

6. Today
• Today the ‘Leaning Tower of Pisa’ is
among the world’s most popular tourist
attractions.
• The final tilt of the tower was stopped at
5.5 degrees, and thanks to strengthening
of the foundations and a restoration
program that is in effect, architects predict
that the Tower will be around for many
centuries to come.