Which garden can you only enter if you are accompanied by children? Where can you find walrus bones, vampire stories and inspiration for red telephone boxes? And since when do you see skateboards and mobile phones in roman mosaics? London's gardens and parks form the green lung of the multimillion-housing capital, but also its heart and soul. Londoners commemorate their beloveds on park benches, they volunteer to keep up community gardens and nature reserves, and they get upset when snails attack their favourite plant. The city's 400-plus green spaces are not only testament to the English love of gardening; they are also steeped in history. Kings hunted here, airships were built in London parks, and many famous Londoners are buried in graveyards-turned-gardens. Our guide leads the way into the unknown: dark corners of major parks, enchanted green paradises, and tiny gardens tucked away in rubbish skips or on the rooftops.