Imagine trying to understand a giant forest by only looking at the edge! That's a bit like how we often think about the ocean. We see the beach, the waves, some fish swimming near the shore. But that's just the beginning!

The ocean is like a huge, watery world, much bigger than any forest. It helps make our air clean and keeps our planet cool, but sometimes we forget how important it is.

Think about it: we mostly see the ocean near the coast, where the water is shallow and warm and for most of us the ocean is just a source of food and fun – a place to go swimming, or surfing. But most of the ocean is deep and dark, like a mysterious cave. It's also cold, and the creatures that live there are specially adapted to survive in those tough conditions. We are just starting to know this amazing depths and we still don't know a lot the fish that live there. 

Did you know that the deepest part of the ocean is called the Mariana Trench? It's located in the Pacific Ocean and it's incredibly deep! At its deepest point, the Challenger Deep, it's about 11 kilometers (almost 7 miles) below the surface! That's deeper than the highest mountain, Mount Everest, is tall!

• Imagine the pressure: The pressure at the bottom of the Mariana Trench is immense, over 1,000 times the pressure at sea level!
• Icy cold: The temperature at the bottom of the trench is just a few degrees above freezing.
• Darkness reigns: Sunlight can't reach these depths, so it's pitch black down there.

Even though it's a harsh environment, scientists have discovered amazing creatures that live in the Mariana Trench, showing us that life can exist in the most extreme places on Earth!

Some super-cool explorers have been diving down to the the Mariana Trench.

• Way back in 1960, Jacques Piccard and Don Walsh made history by becoming the first humans to reach the deepest part of the ocean in a special submarine called Trieste. That was a truly amazing feat!
• In 2012, the famous movie director James Cameron, who made Titanic and Avatar, took a solo trip to the very bottom of the Mariana Trench! He built a special submarine called the Deepsea Challenger to take him there. And while he was able to admire this lunar-like landscape and discover new species, he also spotted some plastic waste. This sad reminder shows us that even the deepest parts of our ocean are impacted by human pollution.

• Just a few years later, in 2019, another adventurer named Victor Vescovo went even deeper than James Cameron, reaching a record-breaking record depth! He used a submarine called the DSV Limiting Factor. 
• And get this! In 2020, an amazing woman named Kathryn Sullivan made history. She was the first woman to reach the deepest part of the ocean! But that's not all – she had also been to space before! How cool is that?
• In 2022, another amazing person made history! Dawn Wright became the first Black person to reach the Challenger Deep.

To get a little taste of what it might feel like to explore the deep ocean, try this: Go into a room in your house and turn off all the lights. Then, use a flashlight to explore the room. How does it feel to be in the dark? What can you see? How do things look? This simple activity can help you imagine what it's like to be in the deep ocean, where it's always dark and there's very little light.

Also, the next time you fly and travel over the sea, try to imagine that you're just seeing the surface. Below that surface, there's a whole universe of life and activity happening and those things could affect your life, like the air you breathe and the weather you experience.

Here are some fun things you can do to learn more about the ocean:

• Build a model of the ocean: Use different colours of clay or play-dough to create layers of the ocean, from the sandy beach to the deep ocean floor.
• Create a deep-sea creature: Imagine a creature that lives in the deep ocean. What would it look like? What would it eat? Draw a picture or build a model of your creature.
• Learn to swim: this will help you explore the sea, next time you have a chance. And it is a lot of fun.