This pentagonal fort covers about 18 hectares.

The pentagonal fort was entered through the south side, facing Paris.

The large pentagonal fort was built of limestone, with walls surrounding a large open court.

This beautifully restored pentagonal fort was built in 1616.

Inside the pentagonal fort is the museum, cool, quiet and often empty.

The pentagonal fort is surrounded by a ditch, which is traversed by fire from the caponiers.

Construction started in 1876 on a roughly pentagonal fort with 48 artillery pieces and a garrison of 691 troops.

The pentagonal fort is surrounded by a ditch defended by counterscarps.

Construction on the new pentagonal fort started in 1874, not far from the old redoubt.

The pentagonal fort has bastions at each of its five points.