Golden Week's most high-concept festival ponders whether the capital can get back in touch with Mother Nature, and become a 'city whose beauty is revered around the world' in the process. How? By floating a bunch of glowing, solar-powered ping pong balls down the Sumida River to simulate what it would look like if the fireflies that once populated the area were to return – because nothing says 'natural' like LEDs. Joking aside, the 'Symphony of Light' on May 6 promises to offer an eye-pleasing spectacle; so much so, in fact, that tickets for prime spots along the riverbank are being sold at ¥1,000 a pop. On the preceding Children's Day, May 5, an armada of boats will carry flags designed by kids down the river during the daytime, followed by an evening parade overseen by artist Katsuhiko Hibino.