Horizon Forbidden West: How to find Vista Point Dunehollow

You won't be able to find Vista Point: Dunehollow in Horizon Forbidden West unless you've finished the Sea of Sands's main objective and drained all of Dunehollow's water. But after that's done, you'll be able to return to Dunehollow (for the Night of Lights errand quest, perhaps). You'll see an "unidentified signal" if you use your Focus inside the Dunehollow dome. Get up near and use your Focus to receive the image fragment at the base of the Vista Point: Dunehollow tower.

Dunehollow is located at the northern end of the Dunehollow dome. Head up that way and you'll notice a ladder dangling off the end of half a bridge (Aloy refers to it as an "overhang"). Climb the ladder, then turn left and go onto the crooked-looking bridge that protrudes to one side. Vista Point: Dunehollow can be found by looking south and calling up the image fragment.

The Vista Point: Dunehollow Datapoint brags about the Vegas Strip's water filtration and recycling system, but makes no mention of the other things that made old Las Vegas renowned, such as gambling, entertainment, and other things that happen in Vegas and stay in Vegas. To fill up the blanks, you'll have to use your imagination.