Thank you for taking the time to view the videos.
The view above the water is quite spectacular too. Here are photos and some other links for information:
http://images.google.is/images?q=%C3...title&resnum=4
http://en.wikipedia.org/wiki/%C3%9Eingvallavatn
http://en.wikipedia.org/wiki/%C3%9Eingvellir
http://www.thingvellir.is/english