Scenery Review : EINN Shannon Airport by Boundless
Back in the post-war "Golden Age" of air travel, aircraft did not have the range or endurance to fly non-stop from Europe to the U.S, so routes had to either fly to Gander in Newfoundland as part of the great circle route, and when Shannon Airport became active, this also became part of the routing.
Shannon Airport evolved from a former flying boat terminal was located at Foynes - a small town southern bank of the River Shannon Estuary and first proposed in 1936, and completed just before WW2. Ireland being a neutral