By George Lewis
NBC News

This is my third trip to Pearl Harbor to cover the anniversary of the surprise attack on Dec. 7, 1941, and the place always gives me goose bumps. There is the graceful swaybacked architecture of the USS Arizona memorial, lying atop the remains of the sunken battleship. There are the old hangar buildings on Ford Island, still pockmarked by Japanese strafing. But most of all, there are the survivors, their ranks diminished by the passing years, and their compelling stories of living through a pivotal moment in American history.

Most are men in their late 80s or early 90s, but the memories of that "day of infamy" are seared permanently in their minds.

As Mal Middlesworth, who was a young Marine stationed on the USS San Francisco, put it, "I got to be standing there with a front row seat to one of the greatest spectacles of the 20th century."

That day, 2,400 Americans lost their lives, almost half of them aboard the Arizona, hit by a 1,700-pound armor-piercing bomb that exploded the ship's ammunition magazine.

Don Stratton, an Arizona survivor who was badly burned, said, "It was a terrible day. It just engulfed us in flames."

Read more: Covering Pearl Harbor, decade to decade

Of the 84,000 Americans in uniform on the Hawaiian Island of Oahu the day of the attack, between two and 3,000 are alive today, and their numbers dwindle with each passing year. That's the big difference I've noticed this time around. Whereas thousands of survivors made it to past observances, only about 120 made it this time. And most of them concede it will probably be their last hurrah.

"It's sad," said Edward Wentzlaff, an Arizona survivor. "You can't lose all them kind of people, those friendships and not let it bother you."

Two of the survivors who died earlier this year, Lee Soucy and Vernon Olsen, are being reunited with their shipmates, their ashes interred on this 70th anniversary beneath the waters of Pearl Harbor, where so many sailors and Marines went down with their ships.

And now, the last remaining survivors look to future generations to keep the memories alive, making this anniversary one laden with sentiment and sadness.