Salginatobelbrücke, Robert Maillart, 1930, Schiers Switzerland.
This springing greyhound of concrete connects the hamlet of Schuders (100 people) with the rest of the alpine road that leads to Schiers (2600 people). Literally it is the middle of nowhere yet it was considered important enough for excellence. Also, it was designed and built within 2 years.
133m x 3.5m, with 90m total height. Yes, that is wide enough for cars. Robert Maillart was a creative genius and understood the capacities of concrete early in the material's development. This bridge is a 3-hinge arch (the main shape of the bridge) with a concrete box girder (the part you walk on), vertical tension members, and concrete piers to connect it to the edges of the ravine.
It was extensively repaired from 1975-1991, improving the waterproofing and drainage, and replacing most of the elements with shotcrete.