In an urban setting, a skyway, catwalk, or skywalk is a type of peway consisting of an enclosed or covered bridge between two buildings. This protects pedestrians from the weather. These skyways are usually owned by businesses, and are therefore not public spaces (compare with sidewalk). Skyways usually connect on the second or third floor (American numbering convention), though they are sometimes much higher, as in Petronas Towers (though this skyway is often referred to as a sky bridge). The space in the buildings connected by skyways is often devoted to retail business, so areas around the skyway may operate as a shopping mall. Non-commercial areas with closely associated buildings, such as university campuses, can often have skyways and/or tunnels connecting buildings.