This is a scene of an <a href="https://en.wikipedia.org/wiki/Ama_(diving)" class="extiw" title="w:Ama (diving)">ama diver</a>'s show in Shima Marineland, Kashikojima, Shima, Mie, Japan. It was called a migratory tank.
<a href="//commons.wikimedia.org/wiki/User:Miyuki_Meinaka" title="User:Miyuki Meinaka">Miyuki Meinaka</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>