Toronto's Bloor Street Viaduct bridges the Don valley; road traffic uses the upper deck, rail traffic uses the lower deck.

A viaduct is a bridge that connects points of equal height in a landscape, usually by bridging a river valley or other eroded opening in an otherwise flat area. Often such valleys have roads descending either side (with a small bridge over the river, where necessary) that become inadequate for the traffic load, necessitating a viaduct for through traffic. Such bridges also lend themselves for use by rail traffic, which requires straighter and flatter routes. It gets its name from an analogy with aqueduct, which must be level, while a bridge for people, pack animals or non-rail vehicles can be hump-backed and gain a structural advantage (i.e., less material or design sophistication needed) from that shape. Bloor Viaduct, Toronto. ... Bloor Viaduct, Toronto. ... }|135px|City of Toronto, Ontario Official Flag]]|Coat Image=[[Image:{{{Coat Image}}}|135px|City of Toronto, Ontario Coat of Arms]]}} {{Canadian City/Disable Field={{{Disable Motto Link}}}}} Motto: Diversity Our Strength {{Canadian City/Location Image is:{{{Location Image Type}}}|[[Image:{{{Location Image}}}|thumbnail|250px|City of Toronto, Ontario, Canada Location. ... The Bloor Street Viaduct, or simply the Viaduct, is the popular name of a bridge that spans the Don River Valley in Toronto, Ontario, Canada, crossing over the Don Valley Parkway and Bayview Avenue as well as the river. ... This article is about the river in Toronto, Canada. ... A subway train pulls into St. ... The Golden Gate Bridge A bridge is a structure built to span a gorge, valley, road, railroad track, river, body of water, or any other physical obstacle. ... Fljótsdalur in East-Iceland A valley is a landform, which can range from a few square miles (square kilometers) to hundreds or even thousands of square miles (square kilometers) in area. ... Diesel and electric trains and locomotives replaced steam in many countries in the decades after World War II. Many countries since the 1960s have adopted High-speed railways. ... Pont du Gard, France, a Roman era aqueduct circa 19 BC, it is one of Frances top tourist attractions at over 1. ...

Some well-known viaducts include:

• Bloor Street Viaduct
• Millau Viaduct
• Glenfinnan Viaduct
• Thelwall Viaduct
• Lethbridge Viaduct