The Leaning Tower of Pisa (the world’s most famous construction mistake)

The Leaning Tower of Pisa is the world’s most famous construction mistake. The architect, Bonanno Pisano,
found his bell tower starting to lean almost immediately after he began to build it. And the lean kept increasing through the centuries, a tourist bonanza for Pisa, that would end if the tower leaned too far and fell.
This picture was taken in 1994, prior to a major engineering effort to stabilize the tower and reduce the lean by 10%. The tower was also closed to visitors. I had climbed it back in 1986, great fun, but disorienting.

Why the lean?

The tower is built on unsuitable ground for such a heavy and tall building. It is only about 6 feet above sea level and built on a riverbed. The underlying ground is made up of layers of sand and clay. The layers are not even and the weight of the building has compressed them. Because the layers are not even, as the ground has compressed, it has sunk more in some places than others.

Only 5 years after work on the building began, it was leaning noticeably to the North. The lean was first noticed during construction of the third floor. During the building of the next three floors, the lean was corrected by building the floors parallel to the ground, and not level with the leaning building. During this phase the tower started to lean the other way. Now it was leaning to the South.

Several plans have been tried over the years to stop the tower from falling. Some of them have been almost disastrous. In 1934 an Italian engineer drilled 361 holes into the base and filled them with mortar. The tower promptly leaned over some more. In 1993 650 tons of lead were hung from the North side of the building to try and stop the lean increasing. For a while it worked.

In 1995, they decided to try and increase the foundations under the South side of the building. They froze the ground using liquid nitrogen, to stop it moving, and then started to remove stones, so they could insert metal rods. What they didn’t know was that the stones they were removing were part of the original foundation of the building. That is the nearest the tower has come to disaster. In one night the lean increased as much as it normally increases in two years. They quickly added another 250 tons of lead and decided to rethink the whole thing.

At this point everyone was just about ready to give up. Then a British engineering professor came up with yet another idea. His plan was to remove ground from under the high side, instead of trying to add ground under the low side. In 1999 work began, and was done very slowly, so that the building wouldn’t get a sudden shock. At the beginning of June 2001, the work was complete, and the tower had been straightened up by about 16 inches, which returns it to the position it held in 1838. The engineers believe that it is safe for at least another 300 years.
So, if they know how, why didn’t they just straighten it up all the way? The answer lies in the tower’s name. It is the Leaning Tower of Pisa and just wouldn’t be the same if it didn’t lean! Some of the residents of Pisa say it would be better to let it fall down, rather than to straighten it all the way.

TOWER BASICS



Official Name: TORRE PENDENTE DI PISA
Function: Bell Tower (Campanile)
Original Architect: Bonanno Pisano
Architect who realized that the Leaning Tower could not be straightened:
Tomasso di Andrea da Pontedera (1275)
Years Built: 1173-1350



Latitude: 43.7167 (43° 43′ 0″ N)
Longitude: 10.3833 (10° 22′ 60″ E)
Elevation of Piazza dei Miracoli: About 6 feet, (2 meters) (DMS)
First Construction Stop: 1178 (War with Firenze)
Year in which lean became obvious: 1178 (Third Story)
Height at which lean became obvious: 10.6 meters (35 ft.)
Level at which Tower Straightens to North: 5 (About 110 meters)
Second Construction Stop: 1185 (War with Firenze)
Later Construction Stop: 1284 (War with Genoa, Major Sea Battle Defeat)
Height: 55.863 meters (185 feet). 8 stories.
Outer Diameter of Base: 15.484 meters
Inner Diameter of Base: 7.368 meters
Weight: 14,700 metric tons
Thickness of Walls at the Base: 8 feet
Direction of Lean: 1173-1250 North, 1272-1997 South

7th Floor Completed: 1319
Bell Tower Completed: 1350
First Bells added: 1198 (Third Floor)
Total Number of Bells: 7, tuned to musical scale
Largest Bell: L’Assunta (The Assumption). Three and a half tons, cast in 1655.
Oldest Bell: Pasquarreccia.
Address: Campo dei Miracoli – the “Field of Miracles”, Pisa, Italia
Year cement injected into base, (blamed for lean acceleration): 1934
Steps to Bell Tower: 294
Number of visitors who climbed to top in 1989: 700,000
Date Closed to Public: 7 January 1990
Date Re-opened to Public: 15 December 2001
Weight of Lead added on North side (picture above): 600 tons (1995)
Amount of tilt recorded overnight in September 1995: 2.5 mm (0.07″)
Weight of Lead added after overnight tilt in September 1995: 230 tons
Rate of Fall in 1990: 1.2 mm (1/20″) every year (“Un millimetre per anno”)
Source: The Guardian (London) August 19 1997
Amount of tilt correction from 1990 – 1999: 25 mm (about 1.0″)
Amount of tilt correction from 1999-2001: 43.8 cm (about 17.25″)
Date that Tower was last at current tilt: 1700

Colosseum of Rome (the Most Dramatic Historic Monuments on Earth)

The Colosseum – the greatest amphitheatre of the antiquity – was built in Rome, Italy, about 1920 years ago. It is considered an architectural and engineering wonder, and remains as a standing proof of both the grandeur and the cruelty of the Roman world.
The Colosseum or Coliseum, originally known as the Flavian Amphitheatre, is a giant amphitheatre in the centre of the city of Rome. Originally capable of seating 50,000 spectators, it was used for gladiatorial contests and public spectacles. It was built on a site just east of the Roman Forum, with construction starting between 70 and 72 AD under the emperor Vespasian. The amphitheatre, the largest ever built in the Roman Empire, was completed in 80 AD under Titus, with further modifications being made during Domitian’s reign.

The Colosseum remained in use for nearly 500 years with the last recorded games being held there as late as the 6th century — well after the traditional date of the fall of Rome in 476. As well as the traditional gladiatorial games, many other public spectacles were held there, such as mock sea battles, animal hunts, executions and dramas based on Classical mythology. The building eventually ceased to be used for entertainment in the early medieval era. It was later reused for such varied purposes as housing, workshops, quarters for a religious order, a fortress, a quarry and a Christian shrine.
 Although it is now in a severely ruined condition due to damage caused by earthquakes and stone-robbers, the Colosseum has long been seen as an iconic symbol of Imperial Rome and is one of the finest surviving examples of Roman architecture. It is one of modern Rome’s most popular tourist attractions and still has close connections with the Catholic Church, whose Pope leads a torchlit procession to the amphitheatre each Good Friday.The Colosseum measures 48 metres (157 ft / 165 Roman feet) high, 189 metres (615 ft / 640 Roman feet) long, and 156 metres (510 ft / 528 Roman feet) wide. Unlike earlier amphitheatres, it was an entirely free-standing structure, constructed on flat ground rather than being built into an existing hillside or natural depression. Its outer wall originally measured 545 metres (1,788 ft / 1,835 Roman feet) and is estimated to have required over 100,000 cubic meters (3,531,466 ft) of travertine stone held together by 300 tons of iron clamps.
The surviving part of the outer wall’s monumental facade comprises three stories of superimposed arcades surmounted by a podium on which stands a tall attic, both of which are pierced by windows interspersed at regular intervals. The arcades are framed by half-columns of the Doric, Ionic, and Corinthian orders, while the attic is decorated with Corinthian pilasters. Each of the arches in the second- and third-floor arcades framed statues, probably honoring divinities and other figures from Classical mythology.
The Colosseum’s huge crowd capacity made it essential that the venue could be filled or evacuated quickly. Its architects adopted solutions very similar to those used in modern stadiums to deal with the same problem. The amphitheatre was ringed by eighty entrances at ground level, 76 of which were used by ordinary spectators. Each entrance and exit was numbered, as was each staircase. The northern main entrance was reserved for the Roman Emperor and his aides, whilst the other three axial entrances were most likely used by the elite.
The arena itself was 83 metres by 48 metres (272 ft by 157 ft / 280 by 163 Roman feet).It comprised a wooden floor covered by sand (the Latin word for sand is harena or arena), covering an elaborate underground structure called the hypogeum (literally meaning “underground”). Little now remains of the original arena floor, but the hypogeum is still clearly visible. It consisted of a two-level subterranean network of tunnels and cages beneath the arena where gladiators and animals were held before contests began. Eighty vertical shafts provided instant access to the arena for caged animals and scenery pieces concealed underneath; larger hinged platforms, called hegmata, provided access for elephants and the like. It was restructured on numerous occasions; at least twelve different phases of construction can be seen.
Hollywood movies reinforced some widespread false impressions about the Colosseum of Rome. Historians doubt that the wholesale martyring of Christians occurred there. And, the image of lions eating the Christians before cheering crowds is likely fantasy. Films have also bolstered the myth that thumbs down meant to kill the person in the arena. It was just the opposite in Roman times. Thumbs up signaled “kill him” and thumbs down, “spare him.”

The Colosseum – Entry €11 (€9 if you’re under 25). Expect a long queue and an even longer wait. You can skip the queue if you decide to take a tour, but if you don’t want a tour, you can STILL skip the queue. If you walk across the street to the Roman Forum, you can buy a day-long pass for €10,better still, a 7-day pass for €20 or a standard Colosseum + Palatine ticket at €11. This pass gets you in to the Colosseum, Palatine Hill, the Baths of Caracalla, and the catacombs. If you don’t want to cram it all into one day, get the pass. Plus, it is nice to buy a slice of pizza and eat in the gardens of Palatine Hill. There are lots of people offering tours in English just outside the entrance to the Colosseum. Inside you can take a tour (English, Spanish, or German) every 30 minutes or so for an additional fee of €3.5 per person. The tours are given by knowledgeable archeologists, but they don’t take you to any areas you couldn’t visit on your own.

The Hermitage of Santa Caterina del Sasso (A picturesque location above the water)

The Hermitage of Santa Caterina del Sasso is a Roman Catholic monastery set in a stunning position clinging to the rock face on the south-east shore of Lake Maggiore. Perched on its “balcony” overlooking the Borromeo Gulf, the monastery is located in the municipality of Leggiuno, in the Province of Varese, the region of Lombardy, Italy. This is one of the most intriguing historical sites on Lake Maggiore. Originally only accessible by boat or via a steep staircase down the cliff from 60m above now you reach it from the lake by climbing a flight of 80 steps or you can descend the 268 steps from the car park above.

The Hermitage was founded in the 12th century by the merchant Alberto Besozzi of Arolo. In 1195 he built a tiny, isolated church in recognition of his deliverance. The present buildings date from the late 13th – early 14th centuries.A legend said that the shrine was used as hermitage by the blessed Alberto Besozzo, who miraculously took refuge on these rocks during a tempest and retired there after a solemn vow to Santa Caterina, the patroness of sailors. The monastery consists of three buildings: the southern convent, the convent and the main church. In 1914 it was declared a national monument. Inside there are some important well-kept frescoes dating from the 14th to the 18th century. Today the monastery is run by a community of Oblate Benedictines.

The inner courtyard of the complex opens onto the church, whose portico is formed of four rounded arches in Renaissance style. Appealing to tourists from all over the world, there is a new possibility this year for those wanting to visit the hermitage: the newly inaugurated elevator that provides easy access for the elderly or disabled.

Lido di Venezia(a beach resort since the 19th century)

The Lido has been famous as a beach resort since the 19th century. Today it is fascinating to see the elegant Art Nouveau and Moorish-style vilals and hotels, the tree-lined avenues and the impressive former premises of the Municipal Casino, the Palazzo del Cinema and the Excelsior Hotel overlooking the beach. At the Hotel Des Bains, Luchino Visconti filmed his celebrated Death in Venice. 

Once fortified and used for military purposes, and theatre of the War of Chioggia between the Genoese and the Venetians /14thC/, the Lido was and still remains the setting for one of the most important of the traditional feasts of the Serenissima; for it is here that the ceremony of the Marriage of the Sea takes place, with a large Venetian crowd in attendance.  The Lido was also where the most illustrious guests were received by the Seigniory. The Church of San Nicolo di Lido is evidence of this past: founded in the 11th century and rebuilt in the 17the century, it has Corinthian columns and capitals. Recently has been opened the Planetarium, one of the most interesting and important of Italy. The Fort of Sant’Andrea is interesting too: built in the 156th C on the plan by Michele Sanmicheli it is perhaps best admired from a vantage point near San Nicolo.