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Modern Wonders of the World
Architectural Wonders of
the World
Ajanta
and Ellora
Alhambra
Bali
Borobudur
Chichen
Itza
Colosseum
and Roman
Forum
Colossus
of Rhodes
Cuzco
and Machu
Picchu
Eiffel
Tower
El
Escorial
Great
Wall of China
Great
Zimbabwe Ruins
Hanging
Gardens
of Babylon
Jerusalem
Light
House of Pharos in Alexandria
Nara
Persepolis
Pyramids
of Egypt
Shwe
Dagon
Sistine
Chapel
St.
Paul's Cathedral
Statue
of Liberty
Statue
of
Zeus
at Olympia
Taj
Mahal
Temple
of
Goddess Artemis
(Diana)
Temple
Palace
of Angkor Wat
Terracotta
Warriors of Xian
Tomb
of
Mausolus at
Halicarnassu
Tower
of London
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Sears
Tower
This
110-storey skyscraper in
Chicago, USA, is the tallest building in the world. Sears Tower is 443
meters
high, which is over 50 meters taller than the Empire State Building in
New York
City. The tower was originally built as the national headquarters of
the Sears,
Roebuck Company.
THE
BEGINNING
People generally agree that the
skyscraper was invented in Chicago, the third largest city in the USA.
In 1871
a fire destroyed a third of the city, and architects set about
rebuilding it.
By this time, steel was being mass produced and in 1852, Elisha Otis
had
invented the lift. New buildings could safely and practically be made
much
taller. The first high-rise building appeared in the city in 1882. This
was the
Home Insurance Company Building. It was the first building to have a
skeleton
structure made entirely of steel and iron. It had ten floors – a
hundred fewer
than Sears Tower, built 90 years later.
BUILDING
UPWARDS
As the demand for land in city
centres grew, people needed to build fast and economically. Skyscrapers
were
the perfect solution. With new materials and technology, the design of
skyscrapers was gradually improved and perfected. Steel girders were
used in
different ways to make a strong framework. Some buildings were made of
tall
steel tubes designed to withstand the winds that blow around the top
levels.
Inside the tubes; individual floors and rooms are rigid so that people
can live
and work safely and comfortably.
THE
ULTIMATE
SKYSCRAPER
It took 2400 workers three
years to build Sears Tower, which was finished in 1973. The tower's
unique
framework is made up of nine square tubes, which form a large square at
the
base. This rests on concrete, rock-filled shafts that are securely
fitted into
the solid rock beneath. The nine welded steel tubes rise 50 floors up.
Then the
building starts to narrow. Seven tubes continue on up to the 66th
floor. Then five rise on to the 90th floor, leaving just two
tubes
to form the top 20 floors. Two television antennae take the building's
total
height to 520 meters - over half a kilometer. The amount of steel used
to build
the framework was enough to make more than 52,000 cars.
OPERATING
THE
BUILDING
This huge building has over
418,000 square meters of space. That's more than 57 football pitches.
The Tower
has 104 high-speed lifts, which divide the building into three separate
zones
and make it easier for people to find their way around. The fireproofed
frame
is covered in a skin made of black aluminium and more than 16,000
bronze-tinted
glass windows. Six automatic window-washing machines clean the whole of
the
building eight times a year.
TOURIST
ATTRACTION
About
1.5 million tourists visit Sears Tower
each year. Two express lifts take them up to the 103rd floor
in just
over a minute. From the tower's Skydeck, visitors have spectacular,
panoramic
views of Chicago. In the building's lobby there is an enormous 'wall
mobile' by
the famous sculptor Alexander Calder.
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