Most waterfalls, you admire from the front. This one invites you to walk behind it. Nabegataki, Kumamoto, on the island of Kyushu. A wide, glowing curtain of white water — about ten meters tall — slides off a smooth rock shelf and falls like liquid light. Follow the little path around, duck under the stone ledge, and the whole world flips. Suddenly you’re standing inside the waterfall. Sunlight pours through the moving wall of water, turning everything gold and green. Moss glows at your feet. A cool mist drifts onto your face. Families step through together, children gasping with delight, everyone reaching out to touch the spray. A Japanese family and visitors from overseas trade huge grins across the curtain, all of them a little wet, all of them laughing. So loved that it’s reservation-only now. You stand behind the falling water, smiling, watching the green forest shimmer through the curtain. It feels like the earth saved a secret just for you.