This was my first ever visit to Palouse Canyon and honestly it is one of the most beautiful places I've ever been. For years I've intended to go see it, and now that I realize what I've been missing I think I should visit there every year! From the viewpoint parking lot it takes about a half an hour to hike down to this point just above the falls.
Palouse Canyon is one of the most spectacular features carved by the Lake Missoula Floods that happened at roughly 40-50 year intervals around 12,000 years ago at the end of the last Ice Age. At the peak of any of those incredibly cataclysmic glacial outburst floods this entire canyon was suddenly deep underwater. For a few days it became merely an underwater channel that from the surface would look like a giant rapid. Each time the glacial dam gave way the floods spilled from northeast of Spokane through many channels across what is now the state of Washington and through the Columbia River Canyon to the Pacific Ocean.
So... when you get your new time machine... be very, very careful if you set it to -12,000 years anywhere near this location!!