An aerial view of the heart of downtown Montreal, this drawing draws more than a century of architecture into a single composition — from the Old Port, the city's birthplace on the St. Lawrence, to the towers that press against the sky. For Montreal's skyline obeys an unusual rule: no building may rise above the summit of Mount Royal, some 233 metres above sea level. The 1000 De La Gauchetière (Lemay and Dimakopoulos, 1992), the city's highest roof at 205 metres, meets that ceiling exactly. Seen from above, the ensemble discloses what the street-level eye cannot: a taut dialogue between nineteenth-century stone, twentieth-century glass, and the mountain that alone remains sovereign over the vertical.