The largest and best known of Iceland's glacial lakes, Jokulsarlon Lagoon is in the south of the country at the end of the Vatnajokull glacier. The lagoon first appeared around 1935 and has been growing ever since with the accelerating melting of the glacier. These days it looks likely to eventually breach the narrow isthmus and join up with the sea, making it an inlet rather than a lake. The Icelanders are keen to stop this happening as the main highway which circles Iceland passes over this narrow strip of land.
The lake is filled with icebergs and a home to birds. The seabird Skua nests on the shores of the lake during summer. There are paths to walk around the edge of the lake and boat trips to get up close and personal with those gleaming blue icebergs.
The lake is an easy, if long, drive from Reykjavik on the main highway; it is possible as a day trip but means many hours in the car (over 4 hours each way). Buses traveling from nearby Höfn to Reykjavik usually stop at Jokulsarlon or you can take an organized tour which will include a boat trip on the lake. Nearby is Skaftafell National Park so consider staying in the area overnight and looking around.
