When we talk about things that are unfathomably big, we usually look outward to the Universe. But we've got something that's so mind-bogglingly big on our very own doorstep, you could take all the land above sea level, chuck it in the ocean, and it wouldn't even come close to filling it all up.

Welcome to the unknowable oceans of Earth, which take up 95 percent of the planet's living space, and could hide 20 Washington Monuments stacked on top of each other.

In the RealLifeLore video above, we explore exactly what it means to have something that's 11 km (7 miles) deep.

We start off small, with humans, elephants, and the largest ship ever built, and get to just 100 metres below the surface, where diving can become deadly if you don't know exactly what you're doing. 

Yep, in a body of water 11 km deep, we humans only get to experience the first 100 metres or so.

That's not including some extraordinary people though, like Herbert Nitsch, who made it to 214 metres down on a single breath.

Once we hit the 500-metre mark, this is the maximum dive depth for blue whales. But if you think that's impressive, imagine something as small as an emperor penguin getting all the way down there - and then add another 35 metres. 

Seriously, penguins, we already knew you were badass, but 535 metres is next level. As the video explains, the water pressure at this depth would be equivalent to a polar bear standing on a quarter.

Zoom down to 1,000 metres, and we hit what RealLifeLore calls the Scary Zone. Why? Well, for the next 10 km, literally everything is shrouded in perpetual darkness, and the pressure is so intense, it'd be like standing on the surface of Venus and dying instantly.

Can you guess what thrives in the Scary Zone? Yep, it's giant squids. But they've got nothing on leatherback sea turtles, which can somehow dive down to 1,280 metres.

Zoom down to 2,000 metres, and life as we know it gets… a little strange. Also, there are epic battles between sperm whales and colossal squids, which can grow up to 14 metres long and 750 kg.

Keep going to 4,267 metres, and this is the average depth of the ocean on Earth. Just think about that for a second. And we've still got 6,733 metres to go.

I'll let the RealLifeLore video above run you through those devastating depths, but it's just say if you dropped Mount Everest in the deepest part of the ocean, it wouldn't even come close to touching the bottom.

And hey, if you're still not impressed by all of that, see if you can come to terms with the scale of the Universe:

H/T Gizmodo