In this seed you will be able to find an underwater temple in MCPE, which was introduced in Minecraft PE version 0.15.9
)! To get an underwater temple you have to walk a bit before you see her! In temple, as expected, you will encounter guards that will attack you if you try to get into the castle.
And so how do you get to the underwater temple?! Once you have appeared in the world of MCPE, you will need to climb a small hill that is in front of you.
Further in the same direction continue to move some time.
When you get to the place where the right side is a pool of lava, you will need to turn right.
Continue along the shore to the spit which is shown in the screenshot below.
Then jump from the end of the braid in the water and you will see a underwater temple with guards!
I think you will have something to explore. Here are some screenshots of the underwater temple!