Copenhagen is a green city with many parks, both large and small. King's Garden (''''), the garden of Rosenborg Castle, is the oldest and most frequented of them all. It was Christian IV who first developed its landscaping in 1606. Every year it sees more than 2.5 million visitors and in the summer months it is packed with sunbathers, picnickers and ballplayers. It serves as a sculpture garden with both a permanent display and temporary exhibits during the summer months. Also located in the city centre are the Botanical Gardens noted for their large complex of 19th-century greenhouses donated by Carlsberg founder J. C. Jacobsen. Fælledparken at  is the largest park in Copenhagen.