Located somewhere within the Land of Lightning's many mountain ranges is a valley called the Valley of Clouds and Lightning (雲雷峡, Unraikyō). It's a water-filled valley covered in clouds or fog. Within this valley is a dark cavern where Killer B, the jinchūriki of the Eight-Tails, trains.
After swearing loyalty to the First Raikage, the Yotsuki clan were given land in this valley. The valley has been greatly devastated due to Killer B launching a Tailed Beast Ball within the area during his fight against Taka.