David Leonard, Toronto

As a little boy obsessed with some of the great engineering feats of the past, I still remember my first subway ride under Toronto's Bloor Street Viaduct. How remarkable it was to pop out from the deep darkness of a subway tunnel - and suddenly, light! For those too brief 15 seconds or so, the Don Valley sprawls below you in all of its vast, beautiful, and challenging nature.

These days I'm an historian, urbanist, and proud booster of Toronto's east end. And I'm still fascinated with this bridge of a 'Skin of a Lion' fame - it birthed the city's prewar east end along the Danforth, allowing the extension of the Bloor st streetcar all the way to Luttrell loop, and later the Bloor Danforth subway was placed under it (thanks RC Harris). These 1920's-1930's streetcar suburbs the Viaduct made are among my favourite places in Toronto.

Even on its own, the bridge has such visual authority; in a city of much modest yet handsome prewar architecture, the bridge's scale and steel arches can't help but impress. In Toronto, we have a tendency to sometimes write off what's spectacular about our own city; in our everyday routines, such as our commutes to and from work, we can easily forget what makes this place special. But travel under the bridge on a subway in mid fall as the colours peak, when the valley's vibrancy abounds and truly shines. It is beautiful. The bridge may cross the valley in a few short seconds, but looking out of the window of a subway train, the bridge invites commuters to marvel at the valley, and connects us to it. For me, it's special every time.