This famous landmark bridge has a weight limit of 17 tonnes. Today some 40,000 vehicles cross Tower Bridge every day and it opens for river traffic about 900 times a year.The Old London Bridge of nursery-rhyme fame was built by Peter of Colechurch between 1176 and 1209, replacing an earlier timber bridge. Because of obstructions encountered in building the cofferdams, the arch spans varied from 15 to 34 ft , the uneven construction resulted in frequent need for repair, but the bridge survived more than 600 years.It is 928 ft (283 m) long and was designed by John Rennie and built between 1824 and 1831. The early wooden bridge was replaced by a stone bridge with houses and a chapel.Its roadway was loaded with a jumble of houses and shops, many projecting out over the river. It was demolished and replaced in the 1820s by New London Bridge, designed and built by John Rennie, Sr. (1761–1821), and his son John Rennie, Jr. In the 1960s it was again replaced; the old masonry facing was dismantled and reerected at Lake Havasu City, Ariz., as a tourist attraction.The buildings were removed from 1756 to 1762. The bridge was many times damaged by fire and was finally removed in 1832 after the opening of a new bridge in 1831. In 1968, London Bridge was dismantled and purchased by Lake Havasu City, Ariz. In 1973 a new concrete bridge replaced the old one. London Bridge was the only bridge over the Thames in London until the construction of Westminster Bridge. In 1825 a new bridge, designed by John Rennie, was opened, as the old one could no longer cope with the increasing traffic. This bridge was widened in 1902, and was the bridge that Dickens had in mind during Oliver Twist. In fact, the steps that used to lead down to the river to the west of the bridge were known as ‘Nancy’s Steps’.

By the end of the 18th century, it was apparent that the old London Bridge — by now over 600 years old — needed to be replaced. It was narrow, decrepit and a hazard to river traffic. In 1799, a competition for designs to replace the old bridge was held, prompting the engineer Thomas Telford to propose a bridge with a single iron arch spanning 600 ft (180 m).

The revolutionary nature of this design won praise but it was never used, due to uncertainty about its feasibility and the amount of land needed for its construction. The bridge was eventually replaced by an elegant structure of five stone arches, designed by engineer John Rennie. The new bridge was built 100 feet (30 m) west (upstream) of the original site at a cost of £2,000,000 and was completed by Rennie's son (of the same name) over a seven-year period from 1824 to 1831. The old bridge continued in use as the new bridge was being built, and was demolished after the new bridge opened in 1831. The current London Bridge was constructed by contractors John Mowlem from 1967 to 1972, and opened by Queen Elizabeth II on March 17, 1973. It is a fairly dull edificecomprising three spans of pre-stressed concrete cantilevers, paid for in part by the sale of the earlier Rennie bridge. It is 928 feet (283 metres) long. The cost of £4m was met entirely by the City of London's Bridge House Estates.

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