Overview
The caldera formed about 110,000 years ago and Usu grew inside it; the 1943 eruption pushed up an entirely new mountain, Shōwa-shinzan, in a farmer’s wheat field over two years, an event a local postmaster documented so carefully that his record became a scientific reference. In 2000 the town was evacuated in time and nobody died, which is why the abandoned road and buried buildings can be walked through. The lake is a hot spring resort and hosted the 2008 G8 summit.
Highlights
Walk the Nishiyama crater trail through the 2000 eruption zone — cracked highway, a drowned kindergarten, steam still rising. The ropeway up Usu gives the crater and the lake in one view. Fireworks are launched from a boat on the lake every night from late April to the end of October.