[Tagging] Tourism=attraction: feature or secondary tag?

[Rory McCann]

On 06/12/2018 08:38, Mark Wagner wrote:
> Yellowstone National Park has attracted a fair few bare
> "tourism=attraction" objects.  How would you tag the following:
> 
> * Boiling River and Firehole Swimming Area, naturally-heated stretches
>    of river that are popular for swimming.

natural=water + leisure=swimming_area ? natural=water + sport=swimming ?

> * Petrified Tree, a large, petrified section of tree trunk.

natural=tree? natural=petrified_tree ?

> * Soda Butte, the rock formation left behind by a long-extinct geyser.

natural=rock ? natural=rock_formation ?

> * Norris Geyser Basin, Upper Geyser Basin, Artist Paint Pots, Fountain
>    Paint Pots, and other named groups of thermal features.

natural=geyser ?

> * Roaring Mountain, a hillside that contains a large number of steam
>    vents.

place=locality ? natural=peak ? natural=hill ?