From Wikipedia:

In July 1923 an American battle monument was built in Belleau Wood. Army General James. G. Harbord, the commander of the Marines during the battle, was made an honorary Marine. In his address, he summed up the future of the site:

"Now and then, a veteran ... will come here to live again the brave days of that distant June," Harbord said. "Here will be raised the altars of patriotism; here will be renewed the vows of sacrifice and consecration to country. Hither will come our countrymen in hours of depression, and even of failure, and take new courage from this shrine of great deeds."