PixlBit

Finally after much effort, I got the Treasure Hunter achievement and two others relating to the underwater city in Minecraft: Xbox One Edition. 

I had to create about four maps and travel a long way to finally discover the location of the underwater city. Then I had to come all the way back and get Mark so he could follow me there so we could attack the city together. The underwater city is full of deadly fish and one really big fish in the center that drops a sponge when killed. I was able to find it in the maze of dimly lit rooms, kill it and bring back its sponge before my potion of air breathing ran out. I got the Treasure Hunter achievement for entering the city, another for killing the big fish, and another when we got back and dried out the sponge in the furnace.

Then I traded emeralds with the village cartographer for the Woodland Map and went in search of the Woodland Manor. I searched for hours in real time: crossing seas, riding horses, rowing a boat, and walking. I was at the right latitude but it was clearly very, very far away longitudinally. I eventually gave up and came back to our village, nearly getting killed by witches several times. They like to sneak up on you and throw poison on you. It's super deadly regardless what armor you are wearing. I had enchanted diamond breast plate mail and it didn't help me at all. 

Finally, in the last few minutes, we decided to go after the Ender Dragon since we'd opened the End Portal a while ago. We were both armored up and ready but we didn't expect the dragon to be able to throw us right off the island with every hit. I swear they beefed up that dragon in this version of the game. That monster made playthings out of us.

Well that ended that seed world. What next? Not sure. Maybe not Minecraft.