Gensei Marsh

Gensei Marsh near Unzen's jigoku hot springs is a designated natural monument and one of Japan's rarest landscapes, formed through a slow process of ecological recovery. Scientific analysis shows the area once looked like the bare, steaming jigoku terrain nearby, but as underground temperatures cooled over thousands of years, life moved in. Sphagnum peat moss established first, followed by Japanese azaleas, insect-eating sundews, and rabbit-ear irises. The marsh now represents a textbook example of ecological succession. Water levels have dropped in recent years, possibly due to climate change, meaning the landscape you see today may look different within a century.