Vast and mysterious, much of the ocean still remains unexplored to this very day.Will mankind ever truly uncover all the hidden truth that lay dormant on the very bottom in darkness, awaiting to be found? These are the top 5 things you didn't know about the ocean. NUMBER 5 Did you know the ocean houses the largest known animal to inhibit our entire planet. That would be the blue whale and weighs over a whopping 150 metric tons. It also has the heart the size of a car and this massive animal has to eat a whole 4 tons of krill every single day just to survive Number 4 Phytoplankton are one of the most important components to life here on earth. Because they populate so much of the entire ocean, they actually give us about half of the oxygen we're able to breath every day. Phytoplankon grow and reproduce at phenomenal rates. 200 million tons of phytoplankton are produced every year in the ocean. Just think of the shape we would be in if we didn't have these little guys helping out the earth! Number 3 If you could extract all the salt from the ocean and engulf all land with it,you would have more than enough to cover 5 feet. That's a lot of salt! The ocean itself is also filled with tons of unmined minerals and vast amounts of unmined gold. So much so that if you were to be able to extract all the unmined gold in the ocean, you'd have enough gold to give every single person (6+ billion people) around 4 kg of solid gold. Chaching! Number 2 Did you know that the Blue fin tuna is the considered one of the fastest fish in the sea and able to swim up to 90 km per hour. They are also highly sought in Asian food markets and sushi bars. They weigh on average around 680 KG. Depending on their size and weight, they can actually sell for a pretty penny. Some have sold for around $25,000! Number 1 Just to get a grasp at how vast the entire ocean is, the Pacific ocean alone is the largest sea in comparison to the rest, and is large enough that it can still outsize every bit of landmass on the planet. It covers a staggering 165.25 Million Square Kilometers.