A new dimension like the nether and end but it’s all water. You’re able to swim fast and mine blocks like normal. It’s not as foggy in the water so you can see farther. There’s under water temples and cities with mermaid villagers that you can explore. Lots of different sea life like sharks, whales, different fish, angler fish(mob), jellyfish, etc. the portal is made from putting coral in a rectangle shape like the nether and placing sea pickles where you would place flint and steel. When activated it’s a really bright blue whirlpool looking animation.
other random things
-colorful pebble block like the ones in fish tanks
-deep sea trenches with creepy fish
-Giant air bubbles you can get inside and move around in faster than swimming
-sunken submarines you can look inside
-you can find random items floating in the water like weapons, armor, and things you usually find when you’re fishing