Château Gaillard is an early example of the use of concentric fortification and machicolation in castle design. Machicolation refers to floor openings in battlements, through which defenders could drop boiling oil or rocks on their attackers. This concentric fortification was formed of three defensive baileys, one inside the other and each separated by dry moats.

Richard the Lionheart built Gaillard very quickly between 1196 and 1198 to defend against Philip II of France. The castle saw a lot of action before finally being abandoned in the 16th century and later demolished by Henry IV of France. However, elements of the outer castle remain, and you can still admire the uniquely ribbed walls of the inner bailey.