The Plus 15, commonly written as “+15,” is a vast network of enclosed pedestrian skywalks located in downtown Calgary, Alberta, Canada. The system connects office towers, hotels, shopping centres, convention facilities, and public buildings through elevated walkways built approximately 15 feet (4.5 metres) above street level, which inspired its name. Designed to allow people to move comfortably through the city during Calgary’s long and extremely cold winters, the network enables thousands of workers, residents, and visitors to travel across downtown without needing to go outside.

Because of its enormous scale and connectivity, the system functions almost like a second layer of the city above the streets, filled with restaurants, cafés, retail shops, office entrances, and public gathering spaces.

The first major section of the Plus 15 system opened in 1970 as part of Calgary’s rapid downtown expansion and modernization. Architect Harold Hanen is often credited with helping develop the concept during the late 1960s. Over the decades, the network continued to grow alongside Calgary’s booming business district, especially during the city’s energy-industry expansion. Today, the +15 remains one of Calgary’s most recognizable urban features and an important part of daily life in the city’s downtown area.

According to the Internet