THE VIKINGS WHO VANISHED FROM GREENLAND
It can bring news.
It carries exports away.
It brings people.
It connects a remote community to markets, rulers, religious institutions, and family networks.
Greenland had very little forest by European standards.
That fact alone created a structural weakness.
The settlers could obtain some local materials, use driftwood, and develop resourceful building practices, but they could not simply replace every imported item.
Iron was especially important.