Bigfoot. The Loch Ness Monster. Sea Monsters. UFOs.

These are just a few of the topics that have, over the decades, drawn in television makers seeking to produce documentaries on the odd and the unexplained here on Earth and beyond. Programs and even series that have, for better or worse, delved into sensationalism and muddied the waters. One of the series that stands out from the pack aired four decades ago on Britain's ITV network bucked the trend to a large extent. Fronted by one of the world'...