In the Pantheon of truly eerie television shows "In Search Of" holds a seat at the head of the table. It's blend of dubiously collected evidence conveyed in documentary form, it's baleful soundtrack and some haunting verite reenactments made for a potent viewing experience.
Between 1976 and 1982, Leonard Nimoy's cold tone helped open the portals of the world's greatest mysteries, from The Yeti to the Mary Celeste. The result was a truly scary show. Still, it is not nearly the scariest project on which Nimoy served as a mouthpiece.
As yet no DVD release of the series, but there are plenty of low res. goodies on youtube to fish through if it tickles your fancy. I recommend starting with Bigfoot...
Also check out "Arthur C. Clarke's Mysterious World" when you get a chance.