Introduction to Lake Tjörnin: Lake Tjörnin is the most famous lake in Reykjavik. Most visitors to Reykjavik stroll around Lake Tönín, which is also home to many museums and the University of Iceland. There are many ducks, seagulls, swans and other wild animals on Lake Toning. The lake is usually covered by ice in winter, but the hot geothermal water will open up some sporadic activity areas for waterbirds.