Modern Engineering Wonders

During the twentieth century, there were great improvements in engineering technology.
These new developments allowed the construction of many amazing tuels, bridges,
towers, and office buildings.  
For centuries, people had dreamed about the possibility of coecting the island of Great
Britain to the mainland of Europe. However, it was only in 1994 that such a link was
completed, when a tuel was dug under the English Chael, between England and
France. The Chael Tuel, also known as the "Chuel," actually consists of three
separate railway tuels. These tuels are about 50 kilometres long. They are located
about 150 metres below the bottom of the sea. Obviously, this was an extremely
challenging project to undertake. As a result of the Chuel, it is now possible to travel
between London and Paris by train. And the trip takes only three hours, of which only 20
minutes are spent inside the tuel!  
A suspension bridge is a bridge that is supported by strong wires that hang from tall
towers. The world's longest suspension bridge is the Akashi-Kaikyo bridge, near the city
of Kobe, Japan. This bridge is nearly 4 kilometres long, and the two towers near the
middle of the bridge are about 2 kilometres apart! It took almost 20 years to design this
bridge, and 10 years to build it. This bridge was designed to withstand extremely strong
winds, because Japan often experiences wind storms called typhoons. The bridge was
also designed to withstand powerful earthquakes, which sometimes hit Japan.  
At the begiing of the twenty-first century, the world's tallest free-standing tower was
the Canadian National Tower, or the CN Tower. The CN tower is 553 metres tall. It is
located in the city of Toronto, within the Canadian province of Ontario. This structure was
built in 1975 as a television and radio tower. Before the CN tower was built, TV and radio
reception in the Toronto area was poor. This was because the TV and radio signals were
blocked by the buildings of downtown Toronto. When the CN tower was built, this
problem was solved. Of course, the CN tower is also a famous tourist attraction. People
can ride in the very fast elevators that take them to observation areas, which are at about
350 and 450 metres above the ground. www.salamzaban.com
Although the CN Tower is the world's tallest tower, it is not an office building. The tallest
buildings in the world are the Petronas Towers, in the city of Kuala Lumpur, Malaysia,
and the Sears Tower, in the American city of Chicago. The Sears Tower, which is 442
metres tall, was completed in 1974. It has 110 floors, and its top floor is the highest office
floor in the world. However, the Petronas Towers reach slightly higher, to a height of 452
metres. The Petronas Towers were completed in 1998.  
Obviously, the late twentieth century witnessed some amazing achievements of
engineering. It will be very interesting to see what new wonders will be constructed in the
twenty-first century!