(Photograph) - Buildings make a city. In simple terms, their sheer number can afford that status. Houses, then places of work and worship, shops and schools, cluster together. As more buildings accumulate, the area rises through the ranks of village and town, swallowing up its satellites on the way, becoming too vast to be contemplated from a nearby hilltop, or crossed on foot in a day.
Out of the dense expanse of bricks and mortar, some buildings rise above others to stand as symbols of a city's pride and identity. Many of London's most striking monuments - from Battersea power station to the Houses of Parliament - are strung along its most prominent natural feature, the Thames. And where the river starts to widen and the City meets the East End a new landmark, the headquarters of the Greater London Authority, is taking shape beside an old one, Tower Bridge. An eco-friendly office block and a Victorian show of strength, reflections of the preoccupations of their respective eras.
In the late 1800s, as the capital spread eastwards, London Bridge, the city's oldest, was creaking under the weight of more than 110,000 pedestrians and 22,000 vehicles every day. A new crossing was needed, so the London Corporation's bridge and subway committee presented engineers with a challenge - to design a way across a busy river with low banks that would allow people to cross over it and boats to go under it. Sir Horace Jones's design, revolutionary for its day, was for a bridge known as a bascule (from the French for seesaw) that employed steam powered hydraulics to raise the road.
In July 1894, its first month of operation, the bridge performed this amazing feat 655 times, nd an awestruck populace christened it the Wonder Bridge. More than a century later, it still performs some 500 times a year.
But whereas Tower Bridge hid its engineering prowess under 31 million bricks, and clad its 11,000 tons of steel with Portland stone and Cornish granite, the new GLA building is transparent, a deliberate design feature meant as a nod to the political will of its future inhabitants. Architect Norman Foster has called it "a democratic building" because it "will allow Londoners to see their elected assembly at work".
Like Tower Bridge, it is technologically ahead of its time. The unusual headlamp shape was created with the help of computer-generated thermal maps to optimise its natural air conditioning, tilted so as not to catch too much direct sunlight, and with staggered floors to provide shade. Solar power will heat the building in winter and bring cool air from boreholes in the summer, meaning it will use just a quarter the energy of an ordinary office block.
Victorian town halls - like their bridges - were imposing, lofty structures, which wore their civic pride like a bold adornment. People-friendly, 21st-century politics frowns on such architectural intimidation, and the GLA building attempts to make a voter-friendly virtue out of its transparency. Times change, and buildings with them. But don't be fooled by appearances. In both these places, the real power is wielded far from our view.
Harvey McGavin. Photograph by Andrew Rafferty.
Architectural directory www.greatbuildings.com
The Tower Bridge Experience www.towerbridge.org.uk
GLA building www.london.gov.ukglanew_buildingindex.htm