Steamy Geyser in Geysir
Geysir is home to one of Iceland's most famous features, the jaw-dropping Gulfoss Waterfall, but its less popular attractions are worth a visit as well. The appropriately-named town has an interesting geyser that shoots boiling hot water up to 200 feet into the air very reliably every three minutes and is definitely worth seeing.
Surrounding the geyser are bubbling mud pots and steam vents like this one. Seen all together, the geothermal area gives Geysir an otherworldly look, like what I would picture the surface of the moon must look like.
On any trip to Iceland, a visit to Geysir to see the stunning Gulfoss Waterfall and the town's famous geothermal area is a worthwhile trip.