I don't think any slot canyon has been photographed more than this one. This is Antelope Canyon, just east of Page, Arizona. And let me tell you, although this image looks serene, the place is absolutely teeming with people and tour groups. I had to reserve a photographer's tour to be allowed to bring a tripod in and, as an added bonus, our guide would shoo away all of the people taking selfies so that we could get some shots of the pristine canyon. It was a mad rush to try to get people out of frame, take pictures, and then move on as the next group wanted to shoot the exact thing I just did. That being said, the light in this place is incredible. I highly recommend a photographer's tour and be prepared to deal with extremes in dynamic range. If you're near the Utah/Arizona border and like taking photos or just seeing something interesting, this is the place to go.