But wealth can become a trap when an economy depends heavily on one export.

Walruses were not waiting conveniently outside the farms.

Important hunting grounds lay far to the north, and reaching them required voyages into difficult waters.

The animals themselves were enormous and dangerous.

The hunting expeditions also had to return safely.

This is a crucial point because trade is not simply about having a valuable object.

It is about moving that object.

A Greenlander could possess a tusk worth a great deal in Europe, but that value meant little if there was no ship to carry it across the North Atlantic.