A two-hour installment of the PBS series “Nova” explores a site in North America that contains what is believed to be a previously unknown Viking settlement. The episode, “Vikings Unearthed,” is scheduled to debut online Monday, April 4, and to air on PBS on Wednesday, April 6.

“The new Canadian site, with telltale signs of iron-working, was discovered last summer after infrared images from 400 miles in space showed possible man-made shapes under discolored vegetation,” The New York Times reports. “The site is on the southwest coast of Newfoundland, about 300 miles south of L’Anse aux Meadows, the first and so far only confirmed Viking settlement in North America, discovered in 1960.”

The discovery could place Vikings at the site 500 years before Columbus traveled to America.

Here’s a teaser …