With 950 ha (2500 acres) Richmond Park is the largest of the Royal Parks and the largest enclosed urban park in Europe. It is a National Nature Reserve, a Site of Special Scientific Interest, a European Special Area for Conservation and a Grade 1 listed landscape. It is also the quietest and at night the darkest place in London. Enclosed as a hunting park by an eight mile (13km) long and nine foot (2.7m) high wall built by Charles 1 in in 1637, it has 300 red and 300 fallow deer that roam freely and a wealth of other wildlife, including 1200 veteran oak trees, 60 species of breeding birds, 400 species of fungi, 160 species of spiders and 9 of the 17 UK species of bat. It has the largest area of acid grassland in the London area and many species of wildflower. If you like history, it has strong associations with Royalty and politicians (three Prime Ministers lived in the Park) and was the site of the Olympic athletes village in 1948. The Park has over 5 million visitors a year, with the most popular reason for visiting being its tranquillity and escape from the stresses and strains of London.