#4 Valentre Bridge
The Valentre Bridge that runs across the Lot River in Cahors in southern France was built from 1308 to 1378. That’s 70 years. It’s said that the bridge took so long to finish that the builder got impatient and called upon the Devil to help with the construction. It was agreed that the Devil would do whatever the builder said until the bridge was completed, after which the Devil would take the builder’s soul.