London Bridge refers to several historical bridges that have spanned the River Thames between the City of London and Southwark, in central London. The current crossing, which opened to traffic in 1973, is a box girder bridge built from concrete and steel. This replaced a 19th century stone-arched bridge, which in turn superseded a 600 year old medieval structure. This was preceded by a succession of timber bridges, the first built by the Roman founders of London. The bridge pictured here is the 19th century bridge designed by John Rennie. The bridge was 928 feet long and 49 feet wide, constructed from Haytor granite. The official opening took place on August 1,1831. In 1896 the bridge was the busiest point in London, and one of its most congested; 8,000 pedestrians and 900 vehicles crossed every hour. It was eventually widened by 13 feet, using granite corbels. Subsequent surveys showed that the bridge was sinking an inch every eight years, and by 1924 the east side had sunk some three to four inches lower than the west side. Detroit Publishing Company circa 1890-1900.