Geography. Before the last ice age ended about 10,000 years ago, Norway was covered by a thick ice sheet. When that ice finally retreated (or melted) its movement across the land formed islands, lakes, rivers and mountains. It also etched-out deep valleys that then filled with sea water forming Norway's fjords. Norway is one of Europe's most mountainous countries, and dominated north to south by the many ranges of the Scandinavian Mountains.