City of London Coat-of-Arms - Tower Bridge Approach, London, UK - Coats of Arms on Waymarking.com

The Heraldry of the World website tells us about the coat-of-arms of the City of London:

Official blazon
Arms: Argent a Cross Gules in the first quarter a Sword in pale point upwards of the last.
Crest: On a Wreath of the Colours a Dragon's sinister Wing Argent charged on the underside with a Cross throughout Gules.
Supporters: On either side a Dragon Argent charged on the undersides of the wings with a Cross throughout Gules.
Motto: 'DOMINE DIRIGE NOS' - Lord, direct us.

Origin/meaning
The arms of London have never officially been granted, but have been recorded at the College of Arms, albeit without supporters and crest. The crest and helmet were granted on April 30, 1957.

The shield combines the cross of St. George with the emblem of the city's patron, St. Paul. The first cathedral dedicated to St. Paul was built in 605 in the city. The patron saint itself already appears on a 13th century seal. The arms appear for the first time on a seal from 1380.The sword has often been described or attributed to the dagger with which Sir William Walworth, Mayor of London, stabbed the rebel Wat Tyler on June 15th, 1381. The arms with the sword, however, predate this event. Another story states that the sword was granted by King Richard II as a reward for William Walworth's services to the King. There are, however, no historical evidences for either story. The dragons appear for the first time on an illustration in a book from 1633. The same book, the Survey of London, by Stow, also first mentions the motto 'Domine dirige nos' (Lord, direct us).

On a seal of the Mayoralty dating from the late 14th century the arms show two lion supporters. These are not seen elsewhere.
The origin of the dragons is not clear, it may be that they are derived from the story of St. George, the patron saint of England, in which the saint kills a dragon. The sword and the dragons thus distinguished the arms of the city from those of England.

The oldest known image of a crest dates from 1539 when they appear on the reverse of the common seal of the city. The oldest image is not very clear and looks like a fan-like object, charged with the cross of St. George. By the end of the 17th century, the crest has developed into the dragon wing. Sometimes the arms were shown with two wings, facing each other.

Besides the dragon wing, the arms are often seen in the 17th-19th century with a Fur Cap. It appeared for the first time in 1677 on a large image of the arms, which were surrounded by the cap, sword, mace, cornucopia, fasces, anchor and key. None of these elements have ever been used officially by the council.

The Tower Bridge Exhibition website tells us about the bridge:

London Bridge was originally the only crossing for the Thames. As London grew, so more bridges were added, although these were all built 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 need mounted for a new bridge to the east of London Bridge, as journeys for pedestrians and vehicles were being delayed by hours. Finally in 1876, the City of London Corporation, responsible for that part of the Thames, decided the problem could be delayed no longer.

The view today from the high level Walkways has changed dramatically, although there are still signs of the area's amazing history. With the aid of photographs and interactive kiosks, visitors to Tower Bridge Exhibition can gain a greater understanding of how life would have been when the idea of a new bridge was originally conceived.

How a Design was Chosen
A huge challenge faced the City of London Corporation - how to build a bridge downstream from London Bridge without disrupting river traffic activities. To generate ideas, the "Special Bridge or Subway Committee" was formed in 1876, and opened the design for the new crossing to public competition.

Over 50 designs were submitted for consideration, some of which are on display at Tower Bridge Exhibition. It wasn't until October 1884 however, 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 8 years, 5 major contractors and the relentless labour of 432 construction workers to build Tower Bridge.

Two massive piers were sunk into the river bed to support the construction and over 11,000 tons of steel provided the framework for the Towers and Walkways. This framework was clad in Cornish granite and Portland stone to protect the underlying steelwork and to give the Bridge a more pleasing appearance.

To learn more about the building of Tower Bridge, the people involved in its construction and why it was needed, visit The Tower Bridge Exhibition where video screenings explain the entire project, including the difficulties faced.

How it Works - Then and Now
When it was built, Tower Bridge was the largest and most sophisticated bascule bridge ever completed ("bascule" comes from the French for "see-saw"). These bascules were operated by hydraulics, using steam to power the enormous pumping engines. The energy created was stored in six massive accumulators, as soon as power was required to lift the Bridge, it was always 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 angle of 86 degrees.

Today, 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 now exhibits within the Tower Bridge Exhibition.

Tower Bridge Exhibition - A History
In 1910 the high level Walkways were closed to the public due to lack of use. People arriving on the bridge preferred to wait at street level for it to close rather then heading up the stairs carrying their heavy loads. In 1982, as part of the new Tower Bridge Exhibition, visitors to the bridge could once again enter the walkways, now fully covered, and experience the amazing panoramic views. Although Tower Bridge is now powered by oil and electricity, the original steam engines maintained by a dedicated team of technical officers remain in their original location for all to see. This area is known as the Victorian Engine Rooms, the second section of Tower Bridge Exhibition. Over the past 28 years, the exhibition has been developed to keep pace with modern day needs without losing its Victorian essence. Through interactive kiosks and video walls along with knowledgeable Guides, visitors can learn about key events in the Bridge's history, ranging from Royal visits to dare devil stunts.

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.

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 driven by Albert Gunton had to leap from one bascule to the other when the bridge began to rise with the number 78 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 Experience.

The City of London website tells us about their role:

The City Corporation has a special role and wide remit that goes beyond that of an ordinary local authority. We look after the City of London on behalf of all who live, work and visit here and have three primary functions.

We support and promote the City as the world leader in international finance and business services.
We provide modern, efficient and high quality local services and policing within the Square Mile for residents, workers and visitors.
We provide valued services to London and the nation as a whole, including our role as one of the most significant arts sponsors in the UK and our support for economic regeneration in the surrounding boroughs.

Many of these services are funded from our own resources at no cost to the public and benefit London and the nation.

It supports and promotes the City as the world leader in international finance and business services and provides local services and policing for those working in, living in and visiting the Square Mile.

It also provides valued services to London and the nation. These include

the Barbican Centre and the Guildhall School of Music & Drama
the Guildhall Library and Art Gallery and London Metropolitan Archives
a range of education provision (including three City Academies)
five Thames bridges (including Tower Bridge and the Millennium Bridge)
the Central Criminal Court at Old Bailey
almost 11,000 acres of open spaces (including Hampstead Heath and Epping Forest)
and three wholesale food markets (Billingsgate, Smithfield and New Spitalfields)

It is also London's Port Health Authority and runs the Animal Reception Centre at Heathrow.

It works in partnership with neighbouring boroughs on the regeneration of surrounding areas and its charity, the City Bridge Trust, donates more than £15m to charity annually.