Ever been in Selfoss?
Lonely Planet says that the only reason to stop is to get fuel&food. WRONG!
Selfoss is the largest city in southern Iceland, as well as an important industrial and commercial center. Probably you'll never heard of it or, worst, you've heard that is better to skip it completely. I strongly disagree and I'm going to illustrate why.
I don't want to fool you, it's a small town. It has about 7000 inhabitants and is about 60km far east from Reykjavík so it's not the first thing that could come in your mind in your Iceland travel planning...
But I've been luck to have a tour of it with @selfosstowntours and now I could tell I know a little more about Iceland. The city born around the end of 19 century after the building of the bridge. Then the city grow slowly until in 1930 the main Skyr production site was build.
You can have a walk around the city in about 1 hour and I believe you should not miss Tryggvaskáli, the most ancient building around; Konungs Kaffi and the plaza around it and if you have the chance, enjoy the swimming pool Sundhöll.
Just "nearby the city" (yes, 30mins it's pretty near for Iceland empty wasteness) you can enjoy a horse riding in Icelandic Horseworld as we've done. The place is nice and suitable for all ages and experience. Riding an Icelandic horse it's pretty different than what I was used to with European horses... they're smaller but a lot stronger and used to rugged terrain, wind and rain. Yeah, the horse, not the rider (me).
Luckily for the night we booked the super nice Greenhouse. The place is nice and cozy, created in the middle-of-nowhere for people to enjoy the hiking around Reykjavik without the hassle of sleeping inside the city. Its main idea is to recreate the "greenhouse" that lays around for the tourist to "grow" their natural interests. Anyway, you can check below how beautiful this place is... not to mention that has 4 or 6 of the best restaurant of the capital inside it as corners.