All the geysers at Yellowstone are hot and while a not-so-long time ago people used to launder their clothes in (or on?) Old Faithful nowadays you can’t even get close to the edge of the water. Not even to dip one little finger in.
Probably for the best since some of these pools are boiling hot.
The Abyss Pool is hypnotic. You could stare into it for hours - it looks bottomless and it is an unnatural blue-ish green. This photo doesn’t do it justice.