I never tire of watching the “World at War” and was especially fascinated by the start of episode three “France Falls” where parts of the Maginot Line are shown as they looked in 1973 along with Laurence Olivier’s masterly narration. I recently found out that these scenes were filmed at the Ouvrage Hackenberg which as the Wikipedia page points out was one of the largest forts of the Maginot line.
Today the fort is maintained by a group of volunteers and is open to visitors. Tours are run daily and I took the tour in English which was the highlight of my 2017 trip. The tour lasts for two and half hours (it feels like 20 minutes!), includes a ride on one of the ammunition trains and working demonstrations of some of the forts armaments. I highly recommend it.
The photos show some then and now pictures from the World at War and before May 1940 along with photos taken during the tour.
Decisive Hours 