Greenwich Park is a former hunting park in Greenwich and one of the largest single green spaces in south-east London. One of the Royal Parks of London, and the first to be enclosed (in 1433), it covers 74 hectares (180 acres), and is part of the Greenwich World Heritage Site. It commands fine views over the River Thames, the Isle of Dogs and the City of London. The park is open from 06:00 for pedestrians (and 07:00 for traffic) all year round and closes at dusk.
More information on the Wikipedia page [1]. The website is [2].