Creative art installation by Leandro Erlich features what appears to be a real swimming pool with people walking beneath the surface of the water.
To make the illusion, thin layer of water (only 10 cm deep) was suspended over glass. Below the glass, there is an empty room that visitors can enter.
Fake swimming pools were installed at the PS1 Art Center in New York and the 21st Century Art Museum in Kanazawa, Japan.
Swimming Pool Illusion in New York