These is no written record of a bridge here until about AD 984, but excavations in 1981 uncovered what may have been the foundations of one of the piers of a Roman bridge.
The wooden bridge was a barrier against the Danes who regularly sailed up the Thames to fight the Anglo-Saxons. Nevertheless, in 1014 the Danish King Olav managed to sail right up to the bridge and destroyed the piles supporting the bridge, and the bridge and the defenders collapsed into the Thames. This is believed to be the origin of the nursery rhyme 'London Bridge is falling down'.
The bridge was rebuilt of wood over the years and used as the main defence against invaders. The last timber bridge was built in 1163.
Work on a new stone bridge started in 1176 and took 33 years to complete. It was 926 ft long and 40 ft wide and was supported by 20 arches with a drawbridge. For 600 years, until Westminster Bridge was built in 1750, this was the only bridge in the city.
The drawbridge was set in the seventh span from the Southwark side and was protected on the capital's side by a gatehouse known as the Drawbridge Tower. The tower served as the place of exhibition for the severed heads of people executed at the Tower of London. The display of heads was later transferred to the Southwark Gate, complete with portcullis, on the second pier from the Southwark side. This gate was the main bastion of the bridge and the city's southern defences.
Over the years many houses and shops were built on London Bridge. This was seen as a way of raising revenue for the upkeep of the bridge. The buildings projected over both sides of the bridge, and one of the first buildings was the Chapel of St Thomas a Becket.
During the reign of Elizabeth I the bridge was restored and many new buildings were added, including a water-mill at the northern end of the bridge. Following fires and the Great Fire of 1666, by the middle of the 18th century the bridge and it's buildings were in poor condition and the buildings were removed for both health and safety reasons.
In 1823 Parliament approved John Rennie's design for a new London Bridge. The foundation stone was laid by the Lord Mayor of London in 1825 and opened by King William and Queen Adelaide in 1831. The new bridge was over 1,005 ft long and 56 ft wide.
The bridge lasted 140 years but it was too narrow and too weak to cope with the traffic. In 1967 work began on demolishing the old bridge, and the new bridge was opened by Queen Elizabeth II in 1973. The bridge has a 105 ft wide roadway with room for 6 traffic lanes and two footpaths. To prevent icing in freezing conditions, a heating system was built below the surface of the roadway and pavements.
The old London Bridge was sold and shipped out in sections to Lake Havasu City in Arizona, USA. Lake Havasu is an artificial stretch of water. Today, it is the focal point of annual London Bridge days held in early October, with the people of Havasu dressing up as Elizabethans, archery contests, pancake races, and square dancing.
In 1984 the Royal Navy warship HMS Jupiter hit London Bridge broadside. The ship suffered considerable damage to her superstructure and the granite parapet of London Bridge was dislodged.
Now and then London Bridge still witnesses the traditional walking of a flock of sheep into the City - a right of all who are Freemen of the City of London.