Þingvellir is the place where Iceland began as a country, and it is one of the few spots in the world where history and geology tell the same story. In the year 930, chieftains from across the island met on a plain beside a lake to set up the Alþingi, an assembly that is often described as the oldest parliament in the world still in some form existing. They gathered each summer at the foot of a great rock wall, listened to the Lawspeaker recite the law from memory, settled disputes and sometimes executed offenders in the river. Around the year 1000 the assembly decided that Iceland would adopt Christianity, and in 1944 the republic was proclaimed here.
The landscape is the second half of the story. Þingvellir sits in a rift valley where the North American and Eurasian tectonic plates are slowly pulling apart, and you can see the break in the cliffs of Almannagjá, a long fissure that frames the walk down towards the plain. Behind it is Þingvallavatn, the largest natural lake in Iceland, with water so clear that divers come to swim in the fissure called Silfra. The area is a national park and a UNESCO World Heritage Site, with birch scrub, lava fields and a quiet river called Öxará that falls into the rift as a small waterfall.
The riding is easy and quite pretty. From Reykjavík side the road climbs gently over the moorland and then drops toward the lake, in long, open bends on good tarmac. Beyond the park, the road to Laugarvatn and the Golden Circle passes through lava fields and wide valleys. In summer it is very busy with coaches and rental cars, so early morning or evening are better, and the speeds are low, with police and cameras in evidence. Wind can be fierce on the open plain.
There is a visitor centre with a cafe, and car park charges apply at the main sites. Mosfellsbær, the nearest large town on the Reykjavík side, has plenty, and Selfoss and the small town of Laugarvatn are good further along the circle. Fill the tank before you get here.
Take half an hour to walk the path along the fissure. The wind, the lake and the grass-covered ruins of old booths give you a sense of what it meant to gather here. Dress warmly, because even in summer the weather can turn quickly.