River Thames to the strong current of the river, but also other river users. Organised swimming events take place at various points generally upstream of Hampton Court, including Windsor, Marlow and Henley. In 2011 comedian David Walliams swam the from Lechlade to Westminster Bridge and raised over £1 million for charity. In non-tidal stretches swimming was, and still is, a leisure and fitness activity among experienced swimmers where safe, deeper outer channels are used in times of low stream. A Thames meander is a long-distance journey over all or part of the Thames by running, swimming or using any of the above
Tunnels underneath the River Thames constructed up to 1999 for the Millennium Dome; and a tunnel to the site of the old Ferranti power station on the east side of the mouth of Deptford Creek. There is also a tunnel between Cottons centre and the old Billingsgate Fish Market near to London Bridge. Citibank used it for cabling at one point; it was large enough for a person to walk through. The Silvertown Tunnel is a new Thames river crossing proposed to supplement the existing Blackwall Tunnel, which will join the Greenwich Peninsula with West Silvertown. There is also a further tunnel about two miles