Umi Jigoku ("Sea hell") is one of Beppu's seven 'Hells', renowned hot spring attractions known for their unique natural appearances (not bathing!).
The pond at Umi Jigoku is a beautiful cobalt blue, which creates a striking contrast against the rising steam and nearby red torii gate. A number of smaller ponds also dot the landscape here. including orange-coloured ones and ones with lotus flowers.