Future (underground) Water Cherenkov Detectors

Water Cherenkov detectors have been, and will continue, providing fascinating results in the fields of neutrino physics and astrophysics. Because its strong potential for a wide range of scientific subjects is well recognized, development of a large water Cherenkov detector has been carried out all over the world. The detector is well matured and basic technology to build the next generation, megaton-class detector is readily available. The physics potential and the status of technical development are reviewed.