Seljalandsfoss

A 60-metre waterfall you can walk behind. A narrow path loops around the back of the cascade into a shallow cave, which is the main reason to stop here rather than just photograph it from the road. You will get properly soaked, so bring a waterproof jacket or accept the consequences.

Seljalandsfoss is visible from Route 1 about 120 km east of Reykjavík (roughly 90 minutes' drive). It's often the first big waterfall people see on a south coast trip. While you're here, walk 5 minutes north along the cliff to Gljúfrabúi, a waterfall hidden inside a narrow canyon — far fewer people bother, and it's arguably more impressive.

The path behind the falls closes in winter when it ices over. Summer evenings with the low sun behind the water are the best time for photos. Parking costs 700 ISK. Budget 20-30 minutes.