Afsluitdijk
The A7 runs across a historic part of Dutch engineering, the Afsluitdijk. This dam was originally created to protect the country's long interior coastline from floods by creating a large freshwater lake. The road over the Afsluitdijk was previously a 2-lane N road, but is now a proper motorway; the upgrade to motorway was achieved by utilising the dike's unused railway reservation for the second carriageway. Its midpoint is near the village of Breezanddijk.
Read more about this topic: A7 Motorway (Netherlands)