Many decades later, it was covered in a time dilation field, causing its inhabitants to experience the following days as hundreds of years. When agents of the Sanctuary Network were able to dissolve the field, everyone and everything born and created after the field appeared was phased out of existence.
Carentan is an actual place and was in fact liberated by Allied troops during the Normandy landing. However, the episodes depicting it were filmed on sets built in Canada.
Notes and References
- Article about the real Carentan on Wikipedia