Þingvellir is where Iceland began to govern itself. In the year 930 chieftains from across the island met at this broad valley to found the Althing, an open-air assembly that is often called the oldest parliament in the world, and it met here for the next eight centuries. The law-speaker recited the laws from a rock on the cliff, and the crowd listened from the plain below. In 1944 the republic of Iceland was proclaimed here, and the valley remains a place of national feeling.
The landscape is as dramatic as the history. Þingvellir lies in a rift valley, where the North American and Eurasian tectonic plates are pulling apart by a couple of centimetres a year. The cliffs of Almannagjá mark the western edge, and walking through the gorge, you can feel the scale of it. A small waterfall, Öxarárfoss, drops into the rift, and the lake nearby, Þingvallavatn, is the largest natural lake in Iceland, clear and cold, with some of the best diving in the world in the Silfra fissure.
The ride from Reykjavik is about forty-five kilometres, and the roads are well surfaced, winding over lava fields and through low birch scrub. Mosfellsbær, about thirty-four kilometres away, is the nearest town of any size, and Hveragerði is slightly closer on the other side, so top up your fuel before you arrive. The unsurfaced mountain road north from here is open only in summer, and conditions can be rough.
Weather is changeable. A sunny morning can turn into a cold, wet afternoon, so bring layers. Summer brings long light and crowds, and autumn brings colour and quiet. In winter, ice and snow can close roads. There is a visitor centre with a café and information about the geology and history. Wander the old assembly ground in the evening light and you will understand why the Icelanders chose it.