Having grown up in the Pacific Northwest surrounded by mountains, lakes, and waterfalls, I'm fairly familiar with nature. So on my first full day in Iceland, I decided to hop on a bus to take a nature tour in a land that was completely new and different to me and went to several locations on the "Golden Circle" route of the Þingvellir National Park.
The first stop we made was, oddly enough, not all that natural; a greenhouse specializing in growing tomatoes. That being said, I had come down with a cold and the tomato soup that they made available to us was fantastic. We were able to wander the endless rows of vines growing while slurping up the fruits of their labor (mind the pun) and not too long after arriving we headed to our next location, a geothermal area in Haukadalur, where we could hike around and watch the geysers: Geysir and Strokkur. The giant bursts of water were fascinating to watch, and all of the geothermal bodies of water are so blue they don't even look real. I learned that a lot of the plants in Iceland are actually taken from other areas of the world with similar climates -such as Alaska- and without the transplanting, those fields of purple lupine wouldn't be here!
After the excitement of water blasting out of the ground wore off, the next stop was Gullfoss waterfall, which we were told is the largest (in volume) waterfall in Europe. The mist from the falling water was spraying me from a half a mile away! Our last stop of the day was a walk through Thingvellir National Park . Please note the sign giving directions to the park and I swear if I had gotten lost it would not have helped me get to where I needed to go. Ergo, I stayed quite close to the tour guide.
After a full 8 hours of driving around the Golden Circle and stopping in these 4 locations, we were dropped back off in Reykjavik. If you decide not to rent a car, there are a lot of these types of tours that I recommend! As an added bonus, most, if not all buses in Iceland have wifi on them. I found that to be a nice addition considering most people on the tours utilize it.