A park is an area of natural, semi-natural, or planted space set aside for human enjoyment and recreation or for the protection of wildlife or natural habitats. It may consist of grassy areas, rocks, soil, and trees, but may also contain buildings and other artifacts such as monuments, fountains or playground structures. In North America, many parks have fields for playing sports such as soccer, baseball and football, and paved areas for games such as basketball. Many parks have trails for walking, biking and other activities. Some parks are built adjacent to bodies of water or watercourses, and these parks may comprise a beach or boat dock area. Often, the smallest parks are in urban areas, where a park may take up only a city block or less. Urban parks often have benches for sitting and