Lit.: "Great Boiling Valley"
Oowaku Valley is a volcanic valley located in Hakone, Kanagawa Prefecture with sulphuric vents from the Hakone Volcano. It was once known as "Hell Valley" and was given its current name by the Meiji Emperor and Empress during their visit.
It is known for its "kuro-tamago," or "black eggs," which are eggs hard-boiled in the hot springs. Eating one is said to add seven years to your life.
Oowaku Valley is accessible via the Hakone Ropeway.