This lagoon is fed by the massive Breiðamerkurjökull glacier coming off the gigantic Vatnajökull ice cap.
Icebergs which are trapped in the lagoon by the small outlet to the sea.
In winter the lagoon freezes over. The car chase in the James Bond film Die Another Day was filmed here.
The lagoon flows out to the sea through a narrow outlet, which makes it difficult for the icebergs to get through.
The bridge over the outlet is a part of the Route 1 ring road.