Perhaps Mono doesnt do justice to the rich colors there as you say but it does add to the feel of an alien and hostile landscape
Taupo and Rotorua in New Zealand are the most well known Geothermal areas in NZ with walks in geothermal active areas, hot pools etc, Rotorua even more so when you drive into the city you notice the rotten egg Sulfur smell but then adjust to it while visiting there