 Complete the following phrase:  In the 20th century the Ardennes was widely thought by leading military strategists to be unsuitable for large-scale military operations, due to its difficult terrain and narrow lines of communications. However, in both World War I and World War II, Germany successfully gambled on making a rapid passage through the Ardennes to attack a relatively lightly defended part of France. The Ardennes became the site of three major battles during the world warsthe 