If you're into animals, you can go puffin and whale watching. If you like natural landscape there's gullfoss falls, geysirs. Also, the ridge separating the North American tectonic plate and Mid-Atlantic plate, you can go scuba diving in the waters that separate it. Iceland has great water so to speak, so a lot of people go to the swimming pools and the geothermal pool blue lagoon is a big attraction. Water is crystal clear wherever you go, so they always make good pictures. Also, food is amazing. Great seafood, and the most popular restaurant is a hot-dog stand. You can Google it and Bill Clinton has even stopped by to eat there. If you're into technology, you can tour their geothermal plant. Iceland is 99% powered by renewable energy so it's pretty neat to get to walk around their plant. There is literally tons to do in Iceland and I'm sure you'll have a great time.