St James's Park is the oldest Royal Park in London, taking its name from a hospital, built in the 13th century for leper patients. It became a hunting park during the reign of Henry VIII and Elizabeth I used it for festivals of all kinds. Through the centuries, the park grounds were gradually altered and opened to the public, with the current design being completed by the Regency architect John Nash. 'Duck island', a mini nature reserve for 17 different bird species on the eastern side of the lake is unmissable. The birds include native English species such as swans, ducks and geese, but also a colony of pelicans, first introduced to the park in 1664 as a gift from the Russian Ambassador.