It truly amazes me that we have satelites that can find a pimple on a gnats ass from 150 miles in space but we can't seem to get a clear photograph of Nessie or Bigfoot or the mother ship? I'm not saying that those things do or don't exist, but rather that no one seems to be able to muster up enough plausible concrete evidence to prove or disprove them. I am aware of the underground rivers that connect many land locked lakes to the oceans. It is certainly not implausible that Nessie is a plesiosaur or even an as yet undiscovered specie of whale.
We don't know shit about the ocean depths because we haven't figured out how to explore them yet. Too many engineering obstacles that we have yet to overcome. No telling what ancient mysteries we have waiting for us to find and unravel.