In a glance, nothing very special about this pool, which you can find in a courtyard of Kanazawa, 21st Century Museum of Contemporary Art situated in Ishikawa, Japan.
It looks like an ordinary pool you see everywhere. But you will be surprised when seeing those people inside the pool, standing instead of swimming, and chatting around. Created by an Argentinian Artist, Leandro Erlich, this pool is actually an optical illusion, which appears as though the pool is completely filled. It even comes with a climbing ladder. In reality, there is a layer of water, about 10cm deep, suspended over transparent glass. Visitors will be surrounded by aquamarine walls that project the illusion that they are underwater.