Have you ever visited an aquarium, peered into a rock pool or perhaps even been snorkelling in the sea? If so, you might have caught a glimpse of some of the weird and wonderful animals that live underwater. This issue, we’re exploring much deeper than ever before – we’re diving to the very depths of Earth’s oceans to discover some truly mind-boggling creatures. You can make a deep sea mobile, experiment with a scuba diver, investigate water pressure, learn about the problem of plastics in the ocean and how we can help to solve it, meet a shipwreck archaeologist and check out a fishy optical illusion. We've even squeezed in a page on how fidget spinners work, with instructions on making your own at home! Dive tanks at the ready everyone, we’re going in!