Glenfinnan Viaduct is a railway viaduct on the West Highland Line in Glenfinnan, Scotland. It was built between 1897 and 1901. Located at the top of Loch Shiel in the West Highlands of Scotland. The 21-arch single track viaduct was one of the largest engineering undertakings using concrete without reinforcing when it was built by Sir Robert McAlpine.
Built entirely of concrete, the viaduct consists of 21 arches, each spanning 15m and has a maximum height of 30m offering spectacular views down Lochaber’s Loch Shiel. (source)