Tower Bridge was completed in 1894, after eight years of construction. However, many people don't realise why it was even built in the first place, or why it is so different from London's other bridges. The information below will fill you in on some of Tower Bridge's fascinating history.

The need for a new bridge

Originally, London Bridge was the only crossing over the Thames. As London grew, so more bridges were added, but these were all to the west of London Bridge, since the area east of London Bridge had become a busy port. In the 19th century, the east end of London became so densely populated that public pressure mounted for a bridge to the east of London Bridge, as journeys for pedestrians and vehicles were being delayed literally by hours. Finally in 1876, the City of London Corporation, who were responsible for that part of the Thames, decided that the problem could be put off no longer.

How a design was chosen

The big problem for the City of London Corporation was how to build a bridge downstream from London Bridge without disrupting river traffic activities. To get as many ideas as possible, the "Special Bridge or Subway Committee" was formed in 1876, and opened the design of the new crossing to public competition. Over 50 designs were put forward for consideration, some of which you can see when you visit the Tower Bridge Exhibition. However, it wasn't until October 1884 that Horace Jones, the City Architect, in collaboration with John Wolfe Barry, offered the chosen design for Tower Bridge as a solution.

The building of the bridge

It took eight years, five major contractors and the relentless labour of 432 construction workers to build Tower Bridge.
Two massive piers had to be sunk into the river bed to support the construction, over 11,000 tons of steel provided the framework for the Towers and Walkways. This was then clad in Cornish granite and Portland stone, both to protect the underlying steelwork and to give the Bridge a more pleasing appearance. You can find out more about the building of Tower Bridge and the people involved in its construction when you visit The Tower Bridge Exhibition.

How it works - then and now

When it was built, Tower Bridge was the largest and most sophisticated bascule bridge ever built ("bascule" comes from the French for "see-saw"). It was a hydraulically operated bridge, using steam to power the enormous pumping engines. The energy created was then stored in six massive accumulators so that, as soon as power was required to lift the Bridge, it was readily available. The accumulators fed the driving engines, which drove the bascules up and down. Despite the complexity of the system, the bascules only took about a minute to raise to their maximum 86 degrees. Nowadays, the bascules are still operated by hydraulic power, but since 1976 they have been driven by oil and electricity rather than steam. The original pumping engines, accumulators and boilers are on show as part of the Tower Bridge Exhibition, and you can also see the current machinery and control cabins when you come on a "Behind The Scenes Tour". (Behind The Scenes Tours must be pre-booked)

Interesting facts

Tower Bridge has a fascinating history, which is explored in full in the Tower Bridge Exhibition. Here are a few interesting facts you may not have known:

• 1910 - The high-level walkways, which were designed so that the public could still cross the Bridge when it was raised, were closed down due to lack of use. Most people preferred to wait at the bottom and watch the bascules rise up!
• 1912 - During an emergency, Frank McClean had to fly between the bascules and the high-level Walkways in his Short biplane, to avoid an accident.
• 1952 - A London bus had to leap from one bascule to the other when the Bridge began to rise with the bus still on it.
• 1977 - Tower Bridge was painted red, white and blue to celebrate the Queen's Silver Jubilee. (Before that, it was painted a chocolate brown colour).
• 1982 - Tower Bridge opened to the public for the first time since 1910, with a permanent exhibition inside called the Tower Bridge Exhibition. The Walkways were glazed for the first time to house the new Exhibition.
• 1993 - The centenary exhibition - The Tower Bridge Experience opened, featuring animatronic models telling the story of Tower Bridge.
• 1994 - Tower Bridge became available to hire for parties and receptions.
• 2002 - The current Tower Bridge Exhibtion opened, refocusing on the magnificent views from the Walkways and the history of the Bridge.
• 2007 - Tower Bridge celebrates 25 years of welcoming visitors to its Exhibition

The Tower Bridge , named after its two impressive towers, is one of London's best known landmarks. This Victorian Bridge is now more than 100 years old. Designed by Wolfe Barry and Horace Jones, and completed in 1894, the middle of the bridge can be raised to permit large vessels to pass the Tower Bridge. It used to be raised about 50 times a day, but nowadays it is only raised 4 to 5 times a week.

The bridge is 60 meter (197 ft) long and its towers rise to a height of 43 meter. From the top of the towers, you have a great view on the center of London. You can also visit the inside of the tower, where you can observe the original mechanism used to raise the bridge.