In this geothermal area, you can admire colourful sulfur crystals and try to hike a short trail.
Wikipedia https://de.wikipedia.org/wiki/Námafjall
More information https://guidetoiceland.is/travel-iceland/drive/namafjall-geothermal-area
Address Iceland
Coordinates 65°38'24.531" N -16°49'16.029" E