 Historically, city planners filled in many of the ravines, and when this was not possible, planners mostly ignored them, though today the remaining ones are embraced for their natural beauty.Ravines have helped isolate some central neighbourhoods from the rest of the city, and have contributed to the exclusivity of certain neighbourhoods such as Rosedale.Thanks to its vast hinterland, Toronto designers have had access to a wide array of raw materials for construction.