Osaka Prefectural Sayamaike Museum

The Sayama pond south of the city of Osaka is Japan’s oldest artificial reservoir, built in 616 to hold water for use on nearby rice fields. The Sayamaike Museum details the still-functional pond’s 1,400-year history while highlighting advances in civil engineering and flood control over the centuries. Its imposing, naked-concrete building was designed by starchitect Tadao Ando and features an eye-catching inner garden with waterfalls.