I camped here (rafting) late one May and heard the strangest sound I've ever heard coming down off the rim around 5 AM. Nobody else heard it, but I was wide-awake, looking at the stars. I can't really describe it, but I'll never forget it. Where is this?
I laughed pretty hard when I figured that one out. How LarryBoy knew about it is beyond me. I scanned a list of CA state parks and when I got to that one I knew it was it w/o even having to check the topo, which I did to confirm it. HAHA
It was a lot of fun, even though the release for that year was only around 300 cfs. Actually got the raft stuck on a big rock at one point. The section I posted is Slickrock Cyn which is really beautiful. Saw almost nobody else, just a couple of friends and myself (well, I didn't actually see myself...).
Yes, @Ben guessed it correctly (Dolores River), and the rapid is named for Marie Curie. She got the ore for her research from a nearby area in Colorado (Uravan). She basically discovered radioactivity, IIRC.