A volcanic crater in a bow-shape valley, Jigokudani has hundreds of multicolor geysers pulsing like the heartbeat of Earth itself. Not to worry, though; the walkways to photo ops have handrails and are very safe. It's a short walk from all Noboribetsu hotels and well worth a look. There's no admission fee or formal open hours. Prepare to explain to your kids that the strong smell came from the earth, not you.
Noboribetsu Onsen, Noboribetsu, 059-0551, Japan