The Serpentine in the context of "Tyburn Brook"

Hyde Park is a 350-acre (140-hectare), historic Grade I-listed urban park in Westminster, Greater London. A Royal Park, it is the largest of the parks and green spaces that form a chain from Kensington Palace through Kensington Gardens and Hyde Park, via Hyde Park Corner and Green Park, past Buckingham Palace to St James's Park. Hyde Park is divided by the Serpentine and the Long Water lakes.

The park was established by Henry VIII in 1536 when he took the land from Westminster Abbey and used it as a hunting ground. It opened to the public in 1637 and quickly became popular, particularly for May Day parades. Major improvements occurred in the early 18th century under the direction of Queen Caroline. The park also became a place for duels during this time, often involving members of the nobility. In the 19th century, the Great Exhibition of 1851 was held in the park, for which The Crystal Palace, designed by Joseph Paxton, was erected.

In British English, a lido (/ˈliːdoʊ/ LEE-doh, /ˈlaɪdoʊ/ LY-doh) is a public outdoor swimming pool and surrounding facilities, or part of a beach where people can swim, lie in the sun, or participate in water sports. On a cruise ship or ocean liner, the lido deck features outdoor pools and related facilities.

The term probably made its way into English via "Lansbury's Lido", a nickname used in the British press for London's Serpentine bathing place. The bathing place was revamped in 1930 as a project of the Labour First Commissioner for Works, George Lansbury, a plaque to whom appears on the Serpentine pavilion to this day. The re-opening garnered significant press attention as a result of Lansbury's introduction of "mixed" bathing. Lido, an Italian word for "beach", forms part of the place names of several Italian seaside towns known for their beaches, such as Lido di Venezia, the barrier beach enclosing the Venetian Lagoon. Like the Lido di Venezia, the Serpentine "Lido" includes an extended area of shoreline. The nickname "Lansbury's Lido" was probably also ironic, given the contrast between the glamour of Venice and the relative squalor of interwar London – not to mention the latter's variable weather.

The Long Water is a recreational lake in Kensington Gardens, London, England, created in 1730 at the behest of Caroline of Ansbach. The Long Water refers to the long and narrow western half of the lake that is known as the Serpentine. Serpentine Bridge, which marks the boundary between Hyde Park and Kensington Gardens, also marks the Long Water's eastern boundary.

The Long Water and the Serpentine are generally considered to be part of one lake.