Located close to the Tower of London and named after it, the Tower Bridge over the River Thames is one of the most famous iconic symbols of the city of London and a very popular tourist attraction. Built more than 120 years ago, it is a combined bascule and suspension bridge, 800 feet (244 m) long between the two 213 feet (65 m) tall Victorian Gothic styled towers constructed on the piers. The 200 feet (61m) high central span of the bridge, between the towers, is split equally into two bascules or leaves, which can lift the two parts of the bridge to an angle of 83 degrees to allow river traffic to pass through. The towers are connected with two high level walkways which can be used by the pedestrians to cross the river, even when the bridge deck is raised. However, since those high level walkways were very rarely used, they were closed to the public in 1910 and were reopened as fully covered passages in 1982.
The Tower Bridge has a long history behind it. Followed by an invasion led by the Roman Emperor Claudius in AD 43, the Romans founded the city of Londinium on the banks of the River Thames. During those days, there was only one bridge over the river, which linked the Roman city to the south bank of the river, till it was abandoned during the 5th century. With the growth and expansion of the city, more bridges were built, which were erected west of London Bridge. But, the area covering the east of the bridge became a busy port, with docks lining the riverside. Gradually, the East End of London became a highly developed commercial area and in the second half of the 19th century it badly needed one more river crossing.
After the Royal assent for a new bridge was granted in 1885, the City of London Corporation held a competition in1876, for a new bridge design, which would cause minimal disruption to the existing river traffic. More than 50 design ideas were submitted, but due to various controversies the winning entry was not chosen until 1884. The approved design was a cooperative project of the City of London Architect, Horace Jones and engineer Sir John Wolfe Barry. They had the idea of a bascule bridge with twin towers and a central section that could be raised to allow tall ships to sail through the central section of the water way.
The mammoth construction project began in 1886 and 432 workers under five major contractors took eight years to complete it in1894. More than 70,000 tons of concrete were sunk into the river bed as the foundation to support the piers and about 11,000 tons of steel was used for the construction of the framework of the towers and walkways. Apart from that, Cornish granite and Portland stones were used for the protection of the steel frame as well as to give it an esthetic look. As Horace Jones, the architect, died in 1886, George D. Stevenson took over the responsibility of the project and he replaced the original brick facade with the more ornate Victorian Gothic Style, to make it a pleasing visual combination with the nearby Tower of London.
Hydraulic steam machines were used to lift the bascules till 1974, when they were replaced by electro-hydraulic drive system. However, in 2000, a computer controlled system was installed, so that the bascules could be raised and lowered remotely. Interestingly, some of the old steam machines are now exhibited as a tourist attraction and is a part of the museum tour of a Tower Bridge.
The Tower Bridge was officially opened by the Prince and Princess of Wales on 30th of June 1894 and immediately it became an undisputed symbol of the city of London.
In 2008 a facelift for the bridge was announced costing £4 million, when it was repainted and a new lighting system was installed in the walkways. It took four years to complete the project. During the Summer Olympic Games, held in London in 2012, the bridge featured in publicity and a set of Olympic rings was suspended from it to mark one month until the start of the games.
Today, the visitors can take the opportunity to descend to see the old Victorian Engine Room, with the original steam engines still in working condition, and they can also climb up to the covered walkway high above the road level for the magnificent panoramic views across London.