http://www.dailymail.co.uk/news/article-1322118/British-fisherman-grapples-giant-piranha-goliath-tigerfish.html
The guy does a show called River Monsters, He goes to all kinds of remote locations listening to the legends and stories of the land regarding monsters that have purportedly killed or taken people from boats, the riverside etc.etc.
He then spends time trying to find out what the real animal could be - though most of the time he's not successful, he always manages to catch some prehistoric looking monster on the end of his hook.
Things like this make me think what is out there, that has yet to be discovered.