By Ron Allen, NBC News Correspondent

BO, Sierra Leone – Ahmed Smart is a well-dressed man who stood out in the midday market crowd in downtown Bo, Sierra Leone’s second-largest city.

He walked up to me with a friendly, inquisitive face, dark glasses shielding his eyes from the intense sun, and asked that inevitable question I hear in places like this: "What are you doing here? What is your purpose?"

Photo by Amber Payne/NBC News

NBC New's Ron Allen chats with Ahmed Smart in a marketplace in Bo, Sierra Leone.

Obviously, I stand out. I probably looked pretty uncomfortable sweating profusely standing there looking like a foreigner.

We were in Bo taking pictures of the market scene for a story about the U.S. Peace Corps returning to Sierra Leone after a 16-year absence during the country's long, bloody civil war.

Thirty-nine volunteers were in training just down the road, learning how to teach secondary-school subjects like math and science. They were also grappling with learning the local language and with their new living arrangements with host families – a huge adjustment. Most have no electricity. They get water from a well. They walk up to 45 minutes each day back and forth to their training, from houses in the bush.

It’s a two-year commitment. "The toughest job you'll ever love," is the Peace Corps motto. The tough part is putting it mildly. However, the tremendous feeling of satisfaction and accomplishment from teaching or helping people in these poor distant communities in other ways, so many former volunteers say, is life-altering and almost impossible to put into words.

Photo by Ron Allen /NBC News

Trying to make a living in Freetown, Sierra Leone.

Memory of an old teacher
All of that brings me back to Smart. When I told him about the story we were working on, a broad smile instantly spread across his face. He let out a long sigh, as his mind’s eye raced back to when he was a young boy. He paused to gather his thoughts. The moment was very emotional for reasons I would soon understand.

"They taught me," he said. "Miss Watson. I remember her even now," he said. "I wish to see her."

Watson, a Peace Corps volunteer, was Smart's sixth-grade teacher. "I wonder whatever happened to her," he thought out loud. (Since we are still reporting from Sierra Leone, we haven’t had a chance to try to find out what did come of Watson back in the States.)

It was some 40 years ago, in the early 1960s, he said. Two American teachers, he couldn't remember the other person’s name, spent a couple of years at his school in the eastern province of Kenema. Smart is now an accountant, a civil servant who works for the local government in Bo.

While we visited the Peace Corps training center, we ran into several former students of volunteers who years later are teaching the newest generation of volunteers. But running into Smart in the craziness that is downtown Bo in the middle of the day was a complete coincidence.

Coming back after 16-year hiatus
We are going to have more stories in the coming weeks about the American volunteers now finding their way here. We spent a couple days with them during what's been an extraordinary adventure in this nation trying to pull itself up from the ashes of a devastating war. The government from President Ernest Bai Koroma on down pushed hard to encourage the Peace Corps to return, as a signal to the rest of the world that the country is peaceful and safe.

Photo by Ron Allen/ NBC News

Life is not easy in Sierra Leone. A child in a hospital pediatric clinic in Freetown.

There's a rich tradition of service here dating back to 1962 shortly after President John F. Kennedy launched the Peace Corps with a challenge to a group of students at the University of Michigan. Nearly 4,000 volunteers have served here since. Even though no volunteers have been here for the last 16 years, that figure still makes Sierra Leone’s one of the largest Peace Corps programs in the world.

Back in downtown Bo, Smart was telling us how he hopes more young people here will go to school, learn trades and find jobs that will help this country develop.

The road where we were standing was loud and somewhat dangerous because of the sea of motorbikes whizzing by, usually with two or even three people perched on the seat. Young people, especially young men, love to use the bikes to dash through the terrible traffic here.

Smart said they’re the people who concern him most. "They're the same men who were fighting in the war," he explained. Now they're idle and he feared that could lead to a return to violence.

As we were about to part, he remembered something else about his years in grade school and his American teacher Watson.

"I'm singing Lord, Lord, Lord truly been good to me…I'm singing Lord, Lord Lord… because you did what the world couldn't do." There were several verses.

"I would like to say a very big ‘thank you’ to her," he said of Watson. The song, like so much else he learned from an American volunteer some 40 years ago, has never been forgotten.