Maybe it doesn’t look like much, but Þingvellir (“Meeting Fields”, pron. “think-vethl-ir”) is super interesting for two reasons. (1) it’s one of Iceland’s several rift valleys, where the North American and Eurasian plates are pulling apart, and (2) it is the original site of the Alþingi / Althing (“general meeting”) where chieftains first met in 930 CE to work out laws and dispense justice. The Alþingi continues, much changed of course, as Iceland’s parliament, making it the oldest surviving parliament in the world.
Þingvellir National Park was established in 1930 to mark the 1,000th anniversary of the Althing. It was later expanded to protect the surrounding natural phenomena, and is now designated a UNESCO World Heritage site.