Kongsberg Silver Mines
The silver mines of Kongsberg, in Buskerud county in Norway, constitute the largest mining field in Norway, with over 80 different mines. It was the largest pre-industrial working place in Norway, with over 4,000 workers at its peak in the 1770s and supplied over 10% of the gross national product of the Danish–Norwegian union during its 335-year-long history: over 450,000 man-years were expended in the production.
Vestfold
Vestfold is the county in Norway with the most traces from the Viking Age. Examples include the Oseberg- and Gokstad Burial Mounds. While the Oseberg Ship was discovered in Tønsberg, the Gokstad Ship was discovered in Sandefjord. The Gokstad Ship is Norway's largest preserved Viking ship. Both ships are now located at the Viking Ship Museum in Oslo. Additional burial mounds are found at Borre mound cemetery and Mølen, an UNESCO Global Geopark. Borre mound cemetery is home to Northern Europe's largest burial mound site from Viking Age.