Maybe it was the way the big tank fired its cannon blast, or how the soldiers advanced across the muddy field, or the excitement of watching a battle unfold before him.
Or maybe it was all of it that held 9-year-old Seamus O'Brien enthralled at the 75th anniversary of the D-Day Invasion at the Old Bethpage Village Restoration on Saturday.
"I like how they're using explosions," said the East Meadow boy, standing with his grandfather on the sprawling field-turned-battlefield, replete with green tents, armored vehicles and artillery, and scads of khaki-clad soldiers firing machine guns.
The day commemorated the allied assault on the beaches of Normandy, France, on June 6, 1944. Many Long Islanders were among the forces who participated in the largest seaborne invasion in history. The re-creation was part of a World War II weekend at the Old Bethpage restoration that continues Sunday.
World War II was the seminal event that shaped the world to come for 75 years, from political boundaries to technology to the sense of American exceptionalism, said Gary Lewi, spokesman for the Museum of American Armor, which is located on the site.
The problem, he said, is that many young people don't know about the epic D-Day Invasion, which set the stage for the allied victory in World War II.
"This is more than an observance," Lewi said. "This is a living classroom."
Under one tent-like tarp, Rob Inslee of Massapequa Park, in full soldier regalia, demonstrated a Nazi-made explosive called a shoe box mine. About the size of a cigarette pack, the wooden box contained a half pound of explosives, he said, and could not be found by a metal detector.
"They won't allow this in a school" for a lesson, said Inslee, 56.
Everyone who attended, guests and participants, seem to have their own back story as to why they were there.
Inslee was an Army paratrooper during the Grenada conflict, and his father served in World War II.
"We can't forget their sacrifice," he said.
Randal Wolfer, 69, of Huntington, said she had two uncles who landed on the French shore during D-Day. She was dressed as a war correspondent, and was eagerly telling people that these women journalists, who were not permitted at the front lines, faced long odds in covering the war, compared with male correspondents.
"Everybody needs to know about the war," Wolfer said. "We're trying to keep this history alive."
Seamus O'Brien, the boy from East Meadow, was already an avid student of the big war. He knew which countries participated on each side and that the reason for the invasion was "to punch the Germans out of France."
His biggest smile of the day, however, came when he posed for a picture with a re-enactor portraying the British leader Winston Churchill, attired in the man's signature black hat, flannel pinstripe suit and long cigar.
Together, they flashed the victory sign.