OISE-AISNE AMERICAN CEMETERY, France -- Thousands of headstones silently testify to the American sacrifice at the Second Battle of the Marne 100 years ago -- a sacrifice the chief of the National Guard Bureau honored recently.

Air Force Gen. Joseph Lengyel was the senior U.S. military attendee at the World War I Centennial Commemoration at Oise-Aisne American Cemetery on July 28, joined by Army Command Sgt. Maj. Christopher Kepner, the senior enlisted advisor to the chief. More than a dozen adjutants general from states that contributed to the American Expeditionary Forces also honored the memory of service members who fought and died in "the war to end all wars."

"We are gathered here to remember the service of Americans who gave 'the last full measure of devotion' to their country," Lengyel said, quoting Lincoln, "and to find meaning in their service through this remembrance."

Remembrance is important in order to sustain an understanding of our obligations in a free society, Lengyel said.

The National Guard comprised 18 of the 43 divisions the United States sent to France in World War I -- about 40 percent of the American Expeditionary Force. More than 103,000 Guardsmen were killed or wounded, 43 percent of all American casualties.

By August 1918, the Second Battle of the Marne left Germany on the defensive, hastening the end of a war that had dragged on for four years, decimating a generation.

"We remember the battles that raged here in the fields, the forests, and the towns," Lengyel said. "We also remember the sacrifice made in the cause of freedom -- because the United States honors her war dead."

Lengyel also took part in other commemorations during his visit. Throughout, he emphasized France's importance as the United States' oldest ally, and he praised France's contributions to NATO.

France represents a core part of the National Guard's history: The force owes the French Garde Nationale its name, first approved for a New York State militia unit in 1825 to honor the Marquis de Lafayette, the former Garde Nationale commander lionized for his contributions to the American Revolution.

As Lengyel visited a World War I commemorative festival in Fere-en-Tardenois, residents lined the streets waving French and American flags. "These events build upon and strengthen our relationships with our allies and partners," Lengyel said.

The town's commemorations included a display of tents, equipment carried by infantrymen, entrenching techniques, and vehicles typical of the era. World War I remains vivid in France.

The war was fought in part on the streets of rural French towns, where the pockmarked walls of houses and public buildings evidence the sustained violence of the Great War.

Descendants of those who endured the fighting, evacuations, death and injury keep their ancestors' memories alive. Many French families can name members who fought and died. They know where they lie, and they bear this legacy with an enduring mixture of pride and a sense of epic tragedy. They also sustain a sincere gratitude for the role the United States played in hastening the war's end.

At Croix Rouge Farm, Lengyel left a wreath honoring the 42nd "Rainbow" Division. A towering bronze memorial rises from French countryside virtually unchanged in a century. A bronze soldier carries the limp body of a fallen comrade across the cornfields.

The Lafayette Escadrille Memorial Cemetery, where Lengyel also laid a wreath, bears tribute to American pilots who volunteered to fly for the French before the United States had even joined the war. It is a memorial to those killed -- and also a symbol of American fighting spirit.

Innovation may be a present day buzzword with high visibility because it's a Defense Department and National Guard priority, but Americans have been innovating throughout the country's history -- like the Lafayette Escadrille Airmen of a century ago.

When they first came to France, there was no Air Force, no aerial combat, and no history of a role for the new technology of flight in war. By war's end, many aerial tactics had been established, pilots were an increasingly important contributor to combat and air power was ascending. By war's end, four National Guard aviators were aerial combat aces and one was awarded the Congressional Medal of Honor.

The general also visited the Chateau-Thierry American Memorial, Aisne-Marne American Cemetery, Belleau Wood, and the Pennsylvania Memorial Bridge in Fismes dedicated to the 28th Infantry Division.

Both Lengyel and Kepner had moments where the enormity of World War I became especially vivid.

For the general, it was the sheer number of American graves, and he found himself walking the lines of 2,289 headstones at the Aisne-Marne American Cemetery alone, consumed in thought, stopping to read names, ranks and states, and to reflect on a generation willing to die for allies' freedom, a generation scarred by brutality previously unimagined, a generation many of whose dreams ended in burial in a foreign field, with thousands more missing in action.

"General Pershing, the AEF commander, said 'time will not dim the glory of their deeds,'" Lengyel said. "We won't let it; we will never forget."

For the command sergeant major, most of whose career was spent serving in the 28th Infantry Division of the Pennsylvania National Guard, it was standing on the 1926 Memorial Bridge in the small town of Fismes, a bridge honoring men who came from his home state and fought the Battle of Fismes in these narrow streets. They had come to the aid of an ally; they found themselves in a special, bloody hell where the fighting was house-to-house, where gains were measured in feet and inches, where the wounded sometimes lay untended, covered in dust, and where the ferocity of battle delayed the burial of the dead for days: thousands of American Soldiers were wounded or killed here.

Lengyel was in France to represent the United States at World War I centenary commemorations on behalf of the Army and the National Guard in his capacities as a member of the Joint Chiefs of Staff and as the chief of the National Guard Bureau. The ceremonies he attended were part of a series commemorating the final year of the war. Active duty and Reserve leaders are taking the lead at other ceremonies, representing the Total Army's contributions to ending the conflict.

The American Battle Monuments Commission and the Army's Center for Military History were among U.S. organizations leading the commemorative ceremonies. The Commission administers, operates and maintains 26 American cemeteries and 29 memorials, monuments or markers in 16 countries.