Just a handful of miles from the eastern on/off ramp for Green River, UT is the Crystal Geyser. It's a bicarbonate geyser (not thermal) that began as a drill hole. It used to spout 130-140 feet, but a previous landowner partially filled it in, so now it only goes 8-12 feet.
In the Labyrinth Canyon WSA is the Bowknot Bend of the Green River. The bend is 8 river miles long, but less than 1/2 miles as the crow flies. There is a trail that goes over this notch, so if a boater can hike up and over & be picked up by their companions as they float down the river.
Outside of Moab, UT, people used to bungie jump off of this arch. Thanks to social media, the BLM became aware of this activity and shut it down.
