You'll discover one of Shigeru Ban's most playful architectural experiments tucked into this quiet Yoyogi park. The Pritzker Prize winner has created transparent glass walls that magically turn opaque when you lock the door, transforming privacy through innovative smart glass technology. During the day, the crystalline structure glows like a lantern in the greenery, while at night it becomes a beacon of warm light that feels more like an art installation than a restroom. Ban's concept challenges our assumptions about public space and privacy, proving that even the most utilitarian architecture can spark wonder.