Eastern Oregon; Grass Lake.
Apparently back in the early part of the last century, this was a really nice place to come. The lake was renown for fishing and there was a hotel – resort, anyone? So, to kill a lot of fish all at once, someone decided to do it with dynamite. The result? The area is volcanic and beneath the lake was a cave or something, made from cooled lava. The dynamite broke the roof of the cave . . . drained the lake . . . lots of dead fish, and that was it.
Now it is a lovely rest stop alongside the road, with a trail, picnic grounds, pet area, and a much welcomed spot. When it rains, I think the lake may fill with water, but for now native grasses fill the lake bed.