Construction began on Leaning Tower of Pisa - August 9, 1173

On this day in 1173, the foundation stones for the Leaning Tower of Pisa were laid. 

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Episode Transcript

Speaker 1 (00:00):
This Day in History Class is a production of I
Heart Radio. Hello, Welcome to This Day in History Class,
where we flipped through the book of history and bring
you a new page every day. Today is August nineteen.

(00:23):
The day was August nine, eleven seventy three. Construction began
on the Leaning Tower of Pisa, a monument now famous
for its unstable foundation and four degree lean. In eleven
seventy two, the widow Berta of Bernardo left sixty salty
or gold coins to the Opena company Les Petrum Santa Maria.

(00:48):
The organization used these coins to buy stones to build
the base of a bill tower. On August nine, eleven
seventy three, the foundation stones were laid for a fight
marble bell tower for the cathedral complex in Pizza, Italy.
Besides the Pizza Cathedral and campanile or freestanding bell tower,

(01:10):
the complex also included a baptistery and cemetery. The architect
of the design for the tower is unknown, but the
tower was set to be one and eighty five feet
or fifty six meters tall. It was built in a
circular ditch on ground made of clay, fine sand and shells,

(01:31):
but by the time three of the towers eight stories
were built. About five years after construction began, it became
clear that the building's foundation was settling unevenly on the
ground that was causing it to tilt slightly, but construction
came to a halt since war broke out between the
city states in Italy. During this break, the foundation was

(01:55):
given time to settle, which probably kept the tower from falling.
Construction on the tower did not begin again until twelve
seventy two, almost a century later. Giovanni di Simone, the
new chief engineer on the project, added extra masonry to
the short side of the tower to try to fix

(02:16):
the lean, but the tower sunk even further with the
additional weight. By twelve seventy eight, when construction once again stopped,
the tower tilted to the south by about one degree
or about two point seven feet. As construction continued and
builders attempted to correct the lean, the degree of the

(02:37):
angle only increased. By thirteen sixty, it was at about
one point six degrees. There are two spiral staircases inside
of the building. When work on the bell chamber began,
builders added six steps from the seventh corners to the
bell chambers floor on the south side, but only built
four steps on the north side. The town hour was

(03:00):
completed around thirteen seventy seven bills were installed in it,
the largest of which was put up in sixteen fifty five,
but despite attempts to correct the lean through methods like
reinforcement and cement crowding, the building kept entering towards collapse.
It reached a tilt of about five point five degrees

(03:21):
or fifteen feet by nineteen ninety. At this point, the
Tower of Pizza was closed and engineers worked on straightening it.
They managed to decrease the lean by more than a foot,
and the tower straightened even more over the following years.
The leaning Tower of Pizza is projected to stay stable

(03:42):
for the next two centuries unless some kind of natural
disaster happens that affects its stability. The cathedral complex is
now known as the Piazza Day Middlecoly or Square of Miracles.
I'm Eve Stepcote and hopefully you know a little more
about history today than you did yesterday. If there's something

(04:04):
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d I h C Podcast. Thanks for showing up. We'll
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(04:30):
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