The Island At The Top Of The World (1974) / Øya Ved Verdens Ende (UK-import)
It is 1908 and Sir Antony Ross (Donald Sinden) from London has co-ordinated a team of explorers to go looking for his missing son in the Arctic Circle. The group's expert is John Ivarson (David Hartman), a professor of Nordic history. On their voyage they stumble into uncharted land - a mysterious valley next to a huge volcano, which they discover is a lost Viking kingdom.