Calgary has the longest elevated walkway network in the world, at over 18 kilometers. It includes dozens of office towers, a dozen residential buildings, half a dozen hotels, and one of the city's largest shopping malls.
http://core.mallmaverick.com/pages/core-photo-gallery
http://everydaytourist.ca/2016/2016/...-but-not-great
http://www.calgarysun.com/2013/04/07...wntown-plus-15
The great thing about the +15 network is that it includes several indoor city parks such as the Devonian Gardens and the Jamieson Place Winter Garden that allow people to enjoy beautiful gardens and greenery year-round. It's also good for the amount of light that is constantly pouring into the glassy bridges. The one bad thing is that it effects street life, but I think people over estimate how badly it effects things. On a nice day, people don't really use the +15, but of course when it's raining and shitty out, it's going to be used and is a well appreciated amenity for the downtown commercial core. Another good thing is that the city has restricted the +15 network strictly to the downtown commercial core. The network does not exist in the residential neighbourhoods which surround the commercial core such as Eau Claire, West End, East Village, Chinatown, or the Beltline, so it has no effect on the vibrancy of any of the neighbourhoods which have high streets. It should also be noted that one of the busiest pedestrian streets in the province, Stephen Avenue, is surrounded by +15s.