The Plus 15 or +15 is a Skyway network in Calgary, Alberta. It is one of the world's most extensive pedestrian skywalk systems, with a total length of 18 kilometres (11 miles) and 62 bridges. The system is so named because the skywalks are approximately 15 feet (approximately 4.5 metres) above street level. (Some Plus 15 skywalks are multi-level, with higher levels being referred to as Plus 30s and Plus 45s.)