Armstrong spent one evening helping kids cut out pieces of styrofoam to make "skyscopes" to measure distances between stars, Pedas said.

"That was the funniest sight, to see him cutting," Pedas said.

He overheard one teenage boy share his story of meeting Armstrong.

"Do you know who that was that looked at my telescope," the boy said, Pedas remembered. "That was the first man that walked on the moon. I'm never going to wash my hand again."

In the years that followed the 17-day cruise, Pedas and Armstrong kept in touch and Pedas called him "an extraordinarily wonderful person."

Although he shied away from the spotlight, Armstrong's achievement truly was "a giant leap for mankind."

Although more than half of the world's population wasn't alive then, it was an event that changed and expanded the globe.

"It's a human achievement that will be remembered forever," said John Logsdon, professor emeritus of space policy at George Washington University.

Those first steps were beamed to nearly every country around the world, thanks to a recently launched satellite. It was truly the first global mass media event, Logsdon said. An estimated 600 million people - 1 out of every 5 on the planet - watched.

The two historical events likely to be long remembered from the 20th Century are the moon landing and the first atomic bomb, said Smithsonian Institution space curator Roger Launius.

"There is no way to overestimate that significance in human history and he is forever linked to that," Launius said of Armstrong.

Just as the voyage of Christopher Columbus split historic eras 500 years ago, so will Neil Armstrong and Apollo 11, said Rice University historian Douglas Brinkley, a specialist in 20th Century history.

"We may be living in the age of Armstrong," said Brinkley, who conducted oral histories for NASA, including sessions with Armstrong.

Clarke, the late science fiction author, wrote that the Apollo 11 moon landing was "one of the great divides in human history; we are sundered from it forever by the moment when Neil Armstrong and Buzz Aldrin stepped out on to the Sea of Tranquility. Now history and fiction have become inexorably intertwined."

Since that day, there's been a common phrase: "If we can send a man to the moon, why can't we ... ?" with the blank filled with a task that seems far less difficult.