Deildartunguhver is the most powerful hot spring in Europe and as such, it is definitely worth visiting. The flow rate is unbelievable: 180 litres per second, at a temperature of 97 °C.
The area that surrounds this hot spring is also home to a specific type of fern, "deer fern", that is not to be found anywhere else.
Interestingly, due to its power, the water serves as a heating for some of the surrounding towns, such as Borgarnes and Akranes. Just imagine it, if you take a shower in these towns, you are basically bathing in this hot spring.
Wikipedia https://en.wikipedia.org/wiki/Deildartunguhver
Address Iceland
Coordinates 64°39'49.029" N -21°24'38.106" E