On a run yesterday to Oban yesterday I stopped at two interesting bridges in scenic locations.
Clachan Bridge carries traffic between the mainland and the Isle of Seil. It stretches things but it's known as the "Bridge across the Atlantic". It was completed in 1793.
Connel Bridge crosses Loch Etive at the Falls of Lora, 5 miles east of Oban. It was constructed in 1903 as a railway bridge. In 1914 a roadway was added (with road traffic using it between trains) The line closed in 1966 and the bridge then carried road traffic only. A walk onto the bridge gives great views up & down the loch.