A fjord is an elongated inlet that extends far inland and is bordered on three sides by land. There are more than 1,700 fjords in Norway and two of them are UNESCO World Heritage Sites. The Norwegian fjords were formed during the last Ice Age by ice, meltwater, and gravel, which together have carved deep valleys over the centuries. The Geirangerfjord is the most famous of Norway's fjords and attracts visitors from all over the world every year.