People have always been fascinated with the hidden, the mysterious, and the unexplained. Every society has its tall tales and ghost stories, its odd legends, and heroes. Also, every society has its stories of strange beasts, dangerous or benign, that live in the twilight world between the everyday and the legendary. Through most of history, people have been closely tied to nature, hunting in forests and having an intimate knowledge of the animals in their regions. So-called "primitive" peoples were walking encyclopedias of the natural world, and yet most believed there were more creatures lurking in those woods than the ones they usually encountered. Even as the world becomes more connected, the belief in strange creatures continues as strong as ever.

Although cryptozoology is often scoffed at and widely considered a pseudoscience, one of the reasons it made men like P.T. Barnum rich and continues to fascinate people today is the fact that people realize they've only scratched the surface when it comes to identifying all the different forms of life on Earth. As Martin DelRio pointed out in The Loch Ness Monster, "Animals previously unknown to science have been found more than once in the past hundred years. For instance, there's the megamouth shark (megachasma pelagios), a fifteen-foot-long creature weighing nearly a ton. The first specimen was discovered on November 15, 1976, when it was found entangled in the drag anchor of a U.S. Navy ship. The new creature wasn't described scientifically until 1983...The megamouth remains the only species in its genus, and the only genus in its order."

In North America, the most debated subject in cryptozoology concerns the existence (or otherwise) of a large, unknown hominid inhabiting the Pacific Northwest of the United States and Canada's West Coast. For many skeptics, this is nothing more than a woodland fairy tale that illustrates the credulity of believers, because they believe it would be impossible for such a creature to exist in a country as heavily populated as the United States yet remain completely unknown to mainstream zoologists. On the face of it, that seems a fair contention, since other large creatures such as bears, mountain lions, elk and many others live in the region. Biologists have been able to study these animals in the wild, to recover remains of dead animals, and even live specimens, but while a great many people have looked, to date, no one has been able to capture a Bigfoot or to find remains or other physical evidence such as hair that can be definitively shown to have come from an unknown hominid. That certainly seems to support the skeptics' case.

While cryptids like Bigfoot and the Yeti have become popular in recent decades, none of them can touch the notoriety of the Loch Ness Monster, a large, unknown creature allegedly living in a loch in the Highlands of Scotland. Was it a relic dinosaur or perhaps an entirely new species? New photographs and new eyewitness sightings fueled a growing debate and transformed the Loch Ness Monster, also known as Nessie, into an instantly recognizable staple of pop culture, to the extent that hundreds of thousands of visitors came to Loch Ness every year in hopes of catching a glimpse of the loch's famous inhabitant.

The Loch Ness Monster remains an international brand and the best-known cryptid in the world, but after almost 100 years of fame and media attention, what do people really know about this cryptid, and is there any proof that there really is something large and unknown living in a remote Scottish loch?