River Thames Thames Estuary), the river is subject to tidal activity from the North Sea. Before the lock was installed, the river was tidal as far as Staines, about upstream. London, capital of Roman Britain, was established on two hills, now known as Cornhill and Ludgate Hill. These provided a firm base for a trading centre at the lowest possible point on the Thames. A river crossing was built at the site of London Bridge. London Bridge is now used as the basis for published tide tables giving the times of high tide. High tide reaches Putney about 30 minutes later than
River Thames were established across the weirs that were built on the non-tidal river, and some of these remained when the locks were built – for example at Benson Lock. Others were replaced by a footbridge when the weir was removed as at Hart's Weir Footbridge. Around 2000, several footbridges were added along the Thames, either as part of the Thames Path or in commemoration of the millennium. These include Temple Footbridge, Bloomers Hole Footbridge, the Hungerford Footbridges and the Millennium Bridge, all of which have distinctive design characteristics. Before bridges were built, the main means of crossing the river was by