This is the Lethbridge Viaduct, better known as the High Level Bridge in Lethbridge, Alberta, Canada. Crossing the Oldman River valley this steel trestle bridge is up to 96 metres (314 ft) high and 1,624 metres (5,327 feet) long, making it the longest railway bridge in Canada.

Although actually, it seems that some people reckon the Lethbridge Viaduct might be “the longest railroad trestle bridge in the world” or perhaps even “the world’s longest and highest steel railroad bridge”. I couldn’t verify any of this, but its definitely got a very cool shadow

There’s more about the Lethbridge Viaduct at Wikipedia where they have an interesting photo of the bridge being built, and they link to a cool ground level photo too.

Thanks to Jackson, Quinn Kuiken, John Fleming and Rob Carlson.