As we planned our Iceland vacation the Fimmvörðuháls trail was at the top of our "must do" list. A few weeks have passed since we made the hike, but we talked about it again today and agree that it's one of the top 4 hikes we've ever done. Although fairly long (at 25 km), the elevation gain is very manageable. There's a tremendous variety to the landscape. And when it comes to waterfalls, Fimmvörðuháls is by far the most impressive waterfall trek we've ever done!