◆ Part of the Scandinavia War Context Pack
You asked about "another one of the museums in the castle." The castle is Akershus Fortress — the medieval stronghold on Oslo's waterfront — and its most affecting museum is Norway's Resistance Museum, built next to the fortress's execution ground. Here's what the fortress is, why the museum is planted exactly there, and the occupation story it carries.
Akershus Fortress is the fortified castle you see on the headland at the west end of Oslo's harbor. It was begun around 1299, held off Swedish sieges for four centuries without ever falling in combat, was rebuilt into a Renaissance royal residence by Christian IV, and is still an active military area — the Norwegian kings are even buried in a mausoleum under its church.
Two museums live inside the walls: the Armed Forces Museum (Forsvarsmuseet), a broad sweep of Norwegian military history, and Norway's Resistance Museum (Norges Hjemmefrontmuseum), which does one thing and does it well — the five years of German occupation and the Norwegian home front that resisted it.
Why it hits harder than a normal museum: it was placed on purpose right beside Retterstedet, the fortress execution site where the Germans shot captured resistance members. The building and the memorial are part of the same argument.
Armed Forces Museum — Forsvarsmuseet. The long view: Norwegian military history from the Middle Ages onward. Free entry.
Resistance Museum — Norges Hjemmefrontmuseum. Tight focus: 1940–45, the occupation and the home front. This is the one to prioritise.
Both are inside Akershus. The fortress grounds — ramparts, cannon, harbor views — are free to walk; the museums are separately ticketed (the Armed Forces Museum is free, the Resistance Museum a small charge).
Before the museum makes sense, the fortress does. Akershus is the reason Oslo grew where it did — put power where you can control the harbor, and everything else follows.
King Håkon V started building Akershus around 1299, after a raid on Oslo exposed how open the town was. Within a year he had moved the kingdom's centre of gravity here from Bergen. The castle guarded the headland and the approaches to the harbor — its whole logic is the water in front of it.
For four centuries Akershus absorbed siege after siege from Sweden — 1308, the 1560s, and Charles XII in 1716 — and was never captured by an attacking army. Oslo sat on the Denmark–Sweden frontier, so the fjord and its fortress were always the prize, and the prize held.
After Oslo's great fire of 1624, King Christian IV rebuilt the city right next to the fortress and renamed it Christiania. The medieval castle was modernised into a Renaissance residence with Italian-style bastions. Under the Castle Church is the royal mausoleum — Haakon VII, Queen Maud, Olav V, and Crown Princess Märtha lie there.
Akershus is still a working military area as well as a monument — headquarters buildings, ceremonial use, state functions, and concerts share the grounds with the tourists. When you walk in, you're on active state property that happens to be 700 years old. For the fortress in the wider arc of Oslo, see the Oslo field guide.
Norway's Resistance Museum was set up as a foundation in 1966 and opened to the public in May 1970 — unveiled by Crown Prince Harald, timed to the 25th anniversary of Norway's liberation. It was shaped by veterans of the resistance itself, which is part of why it reads less like a neutral archive and more like a case being made: this happened, this is how ordinary people answered it.
The permanent exhibition walks you chronologically from the 1940 invasion through the occupation years to the liberation in 1945 — using documents, illegal newspapers, home-made weapons, radio sets, and personal objects rather than spectacle.
The museum's location is not incidental. It sits right beside Retterstedet, the fortress's execution ground, where the Germans shot captured members of the resistance. A memorial marks the place; a plaque there carries the names of those killed at this site.
Detail to hold loosely: sources describe a memorial with 42 names and executions carried out at Akershus in 1945. Far more Norwegians were executed elsewhere (the Trandum forest north of Oslo was the main killing site) — Retterstedet is the symbolic one, chosen for the memorial because it's inside the national fortress. Treat the exact count as the memorial's, not a full tally.
Standing arrangement worth knowing: it's the same fortress where Vidkun Quisling — the collaborator whose name became the word for "traitor" — was himself executed in October 1945 after the war, having been held and tried in the country he'd handed over. The fortress bookends the occupation: resistance members shot at the wall in the war, the arch-collaborator shot there after it.
Five years, compressed. If you read only one thread before you go in, read this one — it's the spine of every case in the museum.
This is the story people come out repeating, and the reason parts of the museum exist. It's also genuinely one of the most effective special operations of the war.
At Vemork, outside Rjukan in Telemark, Norsk Hydro ran the world's first commercial heavy-water plant — a by-product of its fertiliser chemistry. Heavy water can slow neutrons in a nuclear reactor, and Germany's atomic researchers wanted it. Denying them the Vemork supply was worth almost any risk to the Allies.
Early attempts failed badly: a 1942 British glider operation (Freshman) crashed, and its survivors were executed. The job fell to Norwegians.
On the night of 27–28 February 1943, a small team of Norwegian commandos — the parachuted Gunnerside party joined to the Grouse advance men already hiding on the plateau — reached the plant the "impossible" way: down 200 metres into the gorge, across the icy Måna river, up the far cliff, avoiding the guarded bridge entirely.
They placed charges on the heavy-water electrolysis cells and got out before the blast. No shots fired, no lives lost, roughly half a tonne of heavy water destroyed and the plant knocked out for months. Churchill rated the Vemork attacks a major event in the atomic struggle. Later air raids and a 1944 ferry sinking finished the job.
Where to see more: the full-scale site is the Vemork / Rjukan museum in Telemark (hours south-west of Oslo), where you can stand in the actual gorge. The Resistance Museum in Oslo gives you the compact version and the wider occupation context around it.
The resistance story is stirring, and it can crowd out a darker fact the museum does not let you skip. Not everyone was saved, and Norwegian hands were involved in the worst of it.
In the autumn of 1942, Norwegian Jews were rounded up — many arrested by Norwegian police and officials, not only Germans. On 26 November 1942 the cargo ship SS Donau sailed from Oslo's harbor — the same harbor Akershus guards — carrying roughly 530 Jewish men, women, and children to Stettin, and on to Auschwitz. It was the largest of several deportations.
In all, on the order of 770 Jews were deported from Norway; only a few dozen survived. About half the country's Jewish population escaped, most smuggled across the border into neutral Sweden by resistance networks — the same home front the museum celebrates. Both facts are true at once, and the honest version holds them together.
A memorial of empty chairs by the water at Akershus marks the departure point; the deportees' names are commemorated in the city. This is the note to end on quietly rather than the one to lead with.
Because you'd earlier asked about the "collaborator museum," it's worth being precise: this is not that place.
Out on the Bygdøy peninsula (the museum peninsula across the fjord) is Villa Grande — the mansion Quisling requisitioned as his wartime residence and grandly renamed Gimle. Since 2005 it has housed HL-senteret, the Norwegian Center for the Study of the Holocaust and Religious Minorities: a research-and-exhibition institution about the Holocaust in Norway, antisemitism, and minorities — set, pointedly, in the collaborator's own house. That's a separate visit, a separate part of town, and a separate subject from the Resistance Museum inside Akershus. Same war, two very different museums.
| Where | Inside Akershus Fortress, on the harbor headland — a short walk from City Hall and Aker Brygge. Bygningen is up on the fortress grounds; follow signs for Hjemmefrontmuseet. |
| Grounds | The fortress ramparts, cannon, and harbor views are open and free to walk. |
| Museum hours | Broadly daily, roughly 10:00–16:00 (longer in summer). Closed on a handful of dates (1 Jan, 17 May, 24–26 & 31 Dec). Check the day-of before going. |
| Tickets | A small admission for the Resistance Museum; the neighbouring Armed Forces Museum is free. |
| Time needed | About an hour for the Resistance Museum. It's compact and text-heavy — read, don't rush. |
Pair it with the walk. The fortress itself is half the point. Come up from the harbor, take the ramparts and the view, then go into the museum with the geography in your head — you'll understand why power sat here.
Find Retterstedet. Step out to the execution memorial near the museum. The building means more once you've stood at the wall it was built beside.
Mind the pacing. As the Oslo guide warns, don't stack too many indoor museums in a row. This one is emotionally heavy; give it room and follow it with air and water, not another gallery.
On 8 May (Liberation Day) the fortress holds a wreath-laying at Retterstedet and often free entry — a good day to be here if the dates line up.
The castle is Akershus — 700 years old and never taken in battle — and the museum worth your hour is Norway's Resistance Museum, built at the wall where the occupier shot the resistance. It's the tight, honest story of 1940–45: a king who said no, a collaborator who became a common noun, a home front that froze out the enemy and blew up his heavy water, and, held alongside the pride, the harbor from which Norway's Jews were deported. Not the Holocaust center on Bygdøy — that's a different house with a different reckoning.
A travel-context explainer, not academic history. Museum hours and ticket details change — confirm on the museum's official page the day you go. The Retterstedet memorial count (42 names) is the memorial's, not a full national tally of executions. Prepared July 2026 for a family visit to Oslo; part of the Scandinavia War Context Pack.