Denmark
Denmark's National Museum is housed in an 18th century mansion and showcases exhibitions on Danish history and culture, beginning with the Stone Age and continuing through the Renaissance. The special exhibitions are often quite good as well.
Sweden
Located in the vaults of the Royal Palace in Stockholm, Sweden's Royal Treasury houses the regalia, the symbols of the country's monarchy, and the crown jewels.
Sweden
Interesting exhibits on armor and clothing worn by the soldiers and royal family of Sweden.
Sweden
A great 45 minute tour of some of the nicer parts of Stockholm’s waterfront (including the beautiful upscale Strandvägen), you'll follow the Royal Canal as it twists through beautiful parkland, and the inner part of the archipelago. Prerecorded audio guides are provided to each guest so you can hear the tour in your preferred language.
Sweden
A fantastic museum featuring the Vasa, a ship built in the 17th century that sank in Stockholm harbor on her maiden voyage in 1628. The ship was salvaged 333 years later and is still being renovated and restored. At the museum you'll see the Vasa yourself, as well as exhibits about how the ship was built, how sailors on lived on similar ships in the 1600s, and other topics related to maritime history.
Sweden
Sweden's open-air history museum offers buildings from throughout Swedish history and across its various regions. Living history interpreters will tell you about the buildings, most of which you can enter. There's also a zoo featuring animals from throughout Scandinavia.
Norway
A fascinating presentation of the history of the Norwegian resistance against the German occupation during World War II.
Norway
A museum with a collection of 3 Viking ships from the 10th century. Two of the ships are remarkably well preserved—almost completely intact—while one is missing about half its structure. The ships were used in ceremonial burials, so they sank with numerous gifts and artifacts.
Norway
An open-air folk museum containing buildings from Norwegian history, some dating to the medieval period. Highlights include a stave church from the 1200s and farmhouses and schoolhouses with soil and grass roofs.
Norway
Built by King Håkon Håkonsson between 1247 and 1267, Håkon's Hall served as a royal residence and feasting hall. The hall is impressive, and it's not hard to imagine medieval Norsepeople feasting inside.