This blue hole is located in the scenic area of Mi Lake. Remember the mysterious cave where Jon Snow & Ygritte was playing in The Game of Rights? Its here. Grjtagj used to be a thriving bath. However, a lot of geological activities occurred in 1975-1984, causing the water temperature in the cave to rise so high that it was not suitable for bathing. Every year, the Icelandic government will announce the rising temperature of the hole. It is said that it has reached 43 degrees now. It is a bit hot for the hot springs, because I saw a German family come here to make hot springs. Almost only the edge part can enter the water. Its really hot. Don't know how the scene of "The Game of Rights" was filmed at the time? TIPs: Grjtagj has two holes to climb in. The inside is figured out, but climbing up and down is a bit dangerous. The advice of not being healthy is to go in from the two entrances to enjoy the scenery. After visiting the Blue Cave, remember to go to the Lake of Mihu to soak in the hot springs. There are obviously no more people in the Blue Lake, and you can enjoy a private space.