Silfra

[1][3] Þingvellir (Thingvellir) National Park is a UNESCO world heritage area and home to Iceland's first parliamentary assembly called Althingi.

Silfra is spring fed by groundwater originating as meltwater from Langjökull, Iceland's second largest glacier, about fifty kilometres north of the Þingvallavatn Lake.

This water then percolates through the aquifer for thirty to a hundred years before emerging from the fissure springs in the Þingvallavatn Lake fifty kilometres to the south.

To get to the main part of Silfra from the caves, divers must go down through the "toilet" headfirst which is a narrow tunnel to a depth of 16 metres.

[10] Although aquatic life is scarce in the extremely cold water temperatures, it is a habitat for some such as the amphipod called Crymostygius Thingvallensis found only in Thingvellir Lake and the surrounding fissures.

A fish species called the Arctic Char also occasionally venture into Silfra during mating season in August and September.