Hverir is a geothermal field to the east of Reykjahlid, to the side of the ridge known as Namafjall. The area is quite active, with mudpots and sulfurous puddles bubbling and steaming away. You will also see plenty of boiling springs, fumaroles and vents. The area naturally smells very heavily of sulfur, and you can often be engulfed in the steam clouds. A series of pathways meander through the area, which are roped off. Do not wander outside these areas as the area can be very dangerous. …
Yet another of the excellent short walks close to Lake Mývatn
besthike.com 
Now that’s a hot spring I will not be taking a dip in 🙂
Actually I’m surprised NOT to see you in it Rick.
Now those are very cool!
DSD
sulfurous puddles sounds like a hike not to trip over on!