Cities have long sought to preserve historic views of landmarks or mountainous horizons. Architect Tom Brigden maps out protected ‘viewing corridors’ in cities from London to Vancouver

Istanbul
Istanbul - Views of the water were important in Ottoman times, and over the years open views of the Golden Horn and across the Bosphorus have become traditional images of Istanbul. They remain a key part of the city’s character today, although aren’t officially protected sightlines. The controversy surrounding the proposed demolition of three ‘illegal’ apartment towers, chastised for their impact upon views of the old city, in many ways reflects the struggle between opposing visions for Turkey’s future place in the world © Tom Brigden/Purcell Architects