This is Iceland's most powerful waterfall. And Europe's second most powerful waterfall. So that makes it a must see.

You can drive to Dettifoss from the east and the west side. The west side has a better road leading to it and a nice platform to see it from, so usually this is the best option. But if you are adventurous, have enough time and are visiting in summer time, you can also try the east side of the waterfall.

And in case you have some time left, there is a smaller waterfall a little upstream called Selfoss (not to confuse with the town in the south). You can go for a short hike upstream to see that one too.