Many people walk in front of this great monument, which stands nearly 20 feet tall, without pausing to think about the World War I heroes it honors: France’s carrier pigeons.

The statue guards the entrance to the Lille Zoo. On it, peace, represented by a woman, liberates a swarm of pigeons. Below her, a shield crushes a snake that symbolizes the enemy. The bas-relief shows soldiers from the front lines using birds as messengers as a last-ditch effort to communicate with the outer world.

In 1936, the Fédération Nationale des Sociétés Colombophiles erected this monument in honor of the 20,000 pigeons who served and died during the Great War. It also commemorates the pigeon fanciers who were executed at the hands of enemy forces for their involvement.

During World War I, the birds swooped through the skies as part of their missions to transmit key intelligence information. Forces on both sides of the war attempted to control these skybound messengers. In German-occupied territories, civilians were ordered to shoot pigeons to reduce the presence of any Allied avians.

One of the most famous French carrier pigeons who served during the Great War was a bird named Valiant. Though he had been badly injured and gassed, he managed to deliver a message from the ill-fated French troops at the Battle of Verdun before later perishing in his dovecot.

Later technological advances eventually rendered the battle-bound birds largely obsolete. However, France’s Nord department still retains its strong pigeon fancier heritage, as professionals and amateurs alike still participate in training the birds.