MARGRATEN, Netherlands (AP) — In the rolling hills of the southern Netherlands, locals have vowed to never forget the American and other Allied soldiers who gave their lives in the fight to liberate towns and villages from the Nazi occupation in World War II.

Nowhere is the deep-rooted gratitude of the post-war generations more clear than in the 65.5 acres of manicured lawns and white marble headstones of the Netherlands American Cemetery on a hill just outside the village of Margraten.

The hallowed burial ground is hosting a concert Thursday to mark the 80th anniversary of the start of the liberation of the Netherlands.

Hundreds of people like Ton Hermes and Maria Kleijnen have chosen to “adopt” one of the 8,288 Americans buried there.

It’s an act of gratitude and remembrance that started almost as soon as the war ended and endures to this day.

People who adopt a grave visit it regularly and leave flowers on the fallen soldier’s birthday, the day they died, at Christmas, on Memorial Day or whenever else they see fit. Some reach out to families of the dead in the U.S., forming lasting transatlantic friendships.

Hermes and Kleijnen adopted 2nd Lt. Royce D. Taylor, a bombardier with the 527 Bomb Squadron, 379 heavy bomber group, who was killed at age 23 when his B-17 plane was shot down on his third mission over Germany — a raid to Bremen — on Dec. 20, 1943.

Taylor’s grandson, Scott Taylor, from Indianapolis, calls his grandfather his hero. He is also the inspiration behind Scott’s decision to serve in the U.S. Air Force. He flew F-15E Strike Eagle jets over Iraq and Kosovo.

Taylor paid tribute to Maria and to Ton, who chairs the foundation responsible for the adoptions, and all the families who tend graves in the cemetery that is meticulously maintained by the American Battle Monuments Commission.

“I’m very grateful. I can’t say it enough to Ton and Maria that I really am grateful for their efforts to be able to remember my grandfather and then also help other Dutch families to remember the others that are here in the cemetery,” he told The Associated Press as a cool fall wind blew through the rows of headstones.

“I am so grateful at a personal level ... because I can’t care for my grandfather like they can,” he added, after they had placed a fresh bouquet of flowers in front of Taylor’s grave.

He was visiting the cemetery a day ahead of the concert to mark the 80th anniversary of American forces from the 30th Infantry Division, known as Old Hickory, crossing from nearby Belgium into the village of Mesch in what is remembered as the start of the liberation of the Netherlands from four years of brutal Nazi occupation.

While much of the south was quickly freed by Allied soldiers pushing eastwards into Germany, the far more densely populated west of the country, including major cities like Amsterdam and Rotterdam had to wait months for liberation.

Those months included a “hunger winter” when famine killed more than 20,000 Dutch people as a railroad strike was compounded by severe weather to prevent the movement of food and fuel. Some people resorted to eating tulip bulbs to survive.

Hermes, a retired Dutch soldier who served in Bosnia during the Balkan wars of the 1990s, said the timing of their visit to the cemetery on Wednesday — 9/11 — was a reminder of why people should keep alive memories of those who gave their lives for Dutch freedom from tyranny.

“It’s a day which shows that democracy and liberty is very fragile,” he said. “So that is why I think it’s important to adopt the grave and to think about what he did for our liberty. That democracy is vulnerable.”

Taylor agreed.

“It can’t be overstated. If we don’t take the opportunity to remember, then we lose the opportunity to understand the significance of their sacrifice,” Taylor said.

Without that remembrance, “we risk repeating those errors of evil and of occupation and of power and and all of those things ... that happened during World War II,” he added.