Actor Brian Rieper plays a German sent to a Canadian prisoner of war camp in Hitler's Canadians.

Escape from Canada to the neutral ground of the United States was the goal of many imprisoned Nazis during the early years of World War II.

Seems strange, doesn't it?

We know all about the underground railroad from the U.S. to Canada in the era of slavery, as well as the parade of draft dodgers that headed north during the Vietnam War. But the concept of desperate Nazis going the other way is one of many fascinating elements in the documentary Hitler's Canadians, which premieres tonight at 8 on History Television.

Canada, of course, entered World War II in 1939 along with Great Britain, whereas the United States didn't get involved until the Japanese bombed Pearl Harbor in 1941. But both before and after the American entry, a total of 40,000 captured Nazis were dumped into Canadian prison camps, where it was hoped they would be too far away from Europe to cause any more real trouble.

The presence of Nazis on Canadian soil didn't get a lot of publicity at the time, since the government didn't want to cause a panic.

"But once they started escaping, that became a real scandal," said Ted Biggs, co-producer of Hitler's Canadians. "The prison authorities and the Canadian military didn't look too good there for a while.

"All the prisoners were perceived as Nazis, and not all of them were, necessarily. But there were some pretty tough characters running around loose. In war time that was a real fear."

Hitler's Canadians -- which is propelled by interviews with German survivors as well as slick re-enactments -- was inspired by a scary real-life encounter involving Biggs' father Bill.

In 1957 the elder Biggs found himself stranded in a German train station overnight. He was shaken awake by an angry policeman who demanded to see some I.D., but the German cop's mood brightened when he examined Bill Biggs' passport. "I spent the war near your home as a POW," the excited German said.

Years later Bill passed that story along to his son Ted, who got to work researching what he hoped would be a feature film.

"I actually was working on a dramatic script when some friends of mine said, 'Why don't you do a documentary?' " Ted Biggs said. "We hadn't intended for it to take so long. It ended up being a four-and-a-half year process.

"The main challenge was coming up with a simple story arc. There are a lot of different stories and a lot of different escapes, too, more than 600. So mainly we wanted to get a sense of the spirit of the time."

Some of the Germans who tried to escape were hardcore Nazis. Others merely were rebelling against the notion of imprisonment, even though by most accounts the Germans were incredibly well-treated in Canada. Still others saw escape as something of a game, knowing they probably would be caught and returned to camp within a day or two.

Things turned more nasty as the war progressed, with the most zealous Nazis taking out their rage on their own countrymen whose commitment to the cause was waning. But all things considered, here's a telling stat: 6,000 German POWs who spent time in Canada moved here permanently in the years after the war.

"It's important to tell this story for the same reason my father was interested in it," Biggs said. "These Germans had been in terrible battles fighting for what I always had thought of as the wrong side, and still do. But being here in Canada changed them, profoundly and quite quickly.

"They were able to see, even through barbed wire, the possibility that maybe the world wasn't the way the Nazi propaganda machine said it was."