None of the ponds on Hampstead Heath are natural, including the string of six HighgatePonds down the Fleet valley on the eastern side. These were formed in the late 17th century when the upper reaches of the river Fleet were dammed, creating reservoirs which supplied drinking water to the St Pancras area further downstream. Here's my clickable guide to the Highgate ponds [map here], working down from north to south:
Stock pond: It's quite quiet this one, wooded on almost all sides and very much left to its own devices as a nature reserve. Ladies' bathing pond: Don't think young maidens in bikinis, think old matrons sporting bathing costumes (or perhaps rather less). The pond is well screened by trees from the eastern entrance ["Women only. Men not allowed beyond this point"] but you can get a full eyeful from the footpath along the western edge. This unique facility has recently been under threat of closure, forcing the Corporation of London to introduce a £2 admission charge. Further details here. Bird sanctuary pond: It's a pond, and it's a bird sanctuary, what did you expect? In particular expect to see a lot of waterfowl, the odd nesting kingfisher and maybe even local resident twitcher Bill Oddie. Model boating pond: This one's very shallow. Before Playstations, frisbees and hard drugs, young Victorian boys used to spend their free time whipping toy yachts across big lakes, like this one. You don't see much of that sort of activity any more, even round here.
Men's bathing pond: The male equivalent of the oestrogen-soaked pool three ponds north, also recently under threat of closure. Nude bathing is popular, as is jumping into the very cold water from the big jetty in the middle. The bodies on show are a mix of old and wrinkled and young and toned. On a hot day several of the bathers preen themselves on the small lawn outside the entrance after they've finished splashing about in the Fleety waters. Highgate number 1 pond: There's been absolutely no originality whatsoever in the naming of this pond. Some ducks live here. Once home to "The Monster of Highgate Ponds" - a 1961 Children's Film foundation classic.