The Plus 15 or +15 is a Skyway network in Calgary, Alberta. It is the world’s most extensive pedestrian skywalk system, with a total length of 16 kilometers and 86 bridges connecting 130 buildings as of 2022.

Calgary often has severe winters and the walkways allow people to get around the city’s downtown more quickly and comfortably. The busiest parts of the network saw over 20,000 pedestrians per day in a 2018 count.

The system is so named because the skywalks are approximately 4.5 meters above street level. Some Plus 15 skywalks are multi-level, with higher levels being referred to as Plus 30s and Plus 45s.

The system was conceived and designed by architect Harold Hanen, who worked for the Calgary Planning Department from 1966 to 1969. Opening in 1970, the central core of the system is a series of enclosed shopping centers and the city’s flagship department stores.

Double-decker buses, like those seen in London England, will never have a place in Calgary because they won’t fit underneath the Plus 15. A standard for nearly all new downtown construction projects whether that be residential or office is to have connectivity to the convenient Plus 15 Skywalk system. While the Plus 15 network is beneficial both economically and climatically, it also keeps downtown streets safer and less prone to accidents involving pedestrians because there are fewer people street side.

Calgary’s Plus 15 Network was a central plot element in the 2000 film Waydowntown, directed by Gary Burns.

According to Wikipedia