The Frontier

I think that the ocean is a really big frontier. It covers over half our earth and we still don't know what is in its deep waters. How do we know Megalodon is extinct? We don't. Not only that but there are still undiscovered species that we don't even know about swimming, surviving, and evolving. We used to think nothing of the seas, other than they were a salty vast desert of water, but now scientists have created machines like submarines to explore the deep. Think about it, we went from wooden ships to mechanical machinery that can go thousands of feet down.  If we ever do explore most of the ocean it won't be any time soon, I think it will remain a vast mystery forever.