Jellyfish are probably not the most favorite of marine creatures but they sure are fascinating and when you see some of these photos, you'll agree they're actually very beautiful too. We should have respect for them too because they have been around in our oceans for more than 700 million years, making them the oldest known multi-organ animal on Earth. They are a very diverse species too - ranging from the minuscule to the huge and come in an amazing range of shapes and colors. Hold my hand because we're diving into the world of jellyfish. No breathing apparatus necessary!