The oceans and seas surrounding the continents offer a number of wonders, many of which are yet to be discovered by humans. The vast bodies of water that covers over 70% of the planet’s surface, holding around 1.35 billion cubic kilometres of water, has plateaus, valleys, plains, mountains, and trenches on its basin just as they are on the surface layer of the Earth. And, interestingly, the underwater mountains, plains etc. are huge in size compared to those on the dry land. Let's discover the largest seas and ocean in this video.