Stockfish

Ever since the Vikings, Norwegians have exported stockfish, cod that has been dried on huge wooden frames out in the cold, crisp winter air. Dry as a tree bark but rich in protein and low in fat, it has been the perfect travelling - and trading companion. Today, the top destination for stockfish is, perhaps surprisingly, Nigeria. So why do Nigerians spend millions of dollars each year on Norwegian cod? The BBC's Victoria Uwonkunda travels to Lofoten in Norway and Lagos in Nigeria to find out.

Up in the far north of Norway, she goes fishing in the fjords during the cod's annual migration. She meets with Erling Falch, whose family has been in the stockfish business for centuries and who is now the biggest exporter to Nigeria. She finds out about what's so special about Norwegian stockfish.

From a historian, she learns how without cod there would have been no Norway - and traces the popularity of Norwegian stockfish market in Nigeria back to the 1960s and the days of the country's brutal civil war.

And in Nigeria we hear the memories of people who recall the airlifts in the dead of night by Scandinavian pilots who flew in stockfish to try to avert a humanitarian disaster.

Stockfish is now a staple in many homes, and a young, up-and-coming chef cooks Victoria a meal to demonstrate what it is about the fish that makes it so loved that people say soup wouldn't be soup without the depth of flavouring Norwegian stockfish brings.