Žingvellir is a site of historical, cultural, and geological importance and is one of the most popular tourist destinations in Iceland.
It is the site of a rift valley that marks the crest of the Mid-Atlantic Ridge.
It is also home to Žingvallavatn, the largest natural lake in Iceland, with a surface of 84 km² and max depth of114 m.
One of the noted features of the lake is the presence of four morphs of Arctic Charr.
Reference: Wikipedia