The popular actor, who plays Highland warrior Jamie Fraser in the hit time-travel TV series, traveled throughout the country for his Men in Kilts program.
Surprisingly, Heughan's favorite location was a visitor attraction in the centre of Edinburgh, rather than one of Scotland's famous lochs, castles, or glens.
The 43-year-old chose Mary King's Close, a rumored haunted close beneath the capital's streets.
Heughan described his visit to Edinburgh as a "terrifying" experience, adding that he adores the city in general.
Inside the South Street vaults, which were only uncovered in the 1980s and revealed a horrible life for the poorest individuals who would have lived there, is also Edinburgh's City of the Dead.
"I just love that city, especially the wynds and closes off the Royal Mile," he remarked.
"The city beneath the city, which we actually shot for Men in Kilts, didn't make the cut, but Mary King's Close,
when they had the city and it's still there, you can go, there's streets beneath there and shops and everything."