The River Thames
The Thames - pronounced 'tems' - is the river that winds its way through the heart of London, dividing it into [north London]? and [south London]?. The city was created some two thousand years ago as a port (One of London's roads is called Aldwych, which comes from Old English meaning Old Port. This is possable in reference to the location of early Roman ports on the Thames); this original location remains the city's core, and is known still as the City of London. The eastern end of the section of the river that passes through London is the Docklands, which were, from the 17th to mid-20th centuries, the busiest part of the city, playing home to a huge trade of seaborne shipping. Note - it's always described, archaically, as 'the River Thames', or just 'the Thames' - never 'the Thames River'.
There are river buses that can take you up and down the river, as well as numerous [river cruises]? and also [floating restaurants]?. There are of course also numerous bridges passing over it and tunnels passing under it. At Woolwich in the east there are also 3 ferries that operate to cross the Thames. These ferries are free to use and are the first means of crossing the Thames as you travel upstream along the Thames in London
There are also many tributaries which flow into the River Thames, most of them culverted, or 'lost' underground. These include the rivers Fleet and Efra.