terrain

i want please , a hole in the ground which under is a big empty ball ( sphere ) in the ground with 1/3 filled with water at the bottom and there is a treasure or chest at the bottom , the entrance of the empty ball in the ground is a open hole area of like 5x5 or 10x10 or 12x12 or more in a round shape horizontal in the ground, ( the top of the giant empty Sphere in the ground )

the hole of the big empty space like a empty ball in the ground could be loaded many time around the minecraft world( chunks). when you fall in it by the top hole on the ground , there is 100 % chance to fall in the water at the bottom , its a visible hole but you cant die falling in.

many year ago i asked for some caves paths to be filled with water, you guys did , thank you