Gamlebyen is the best-preserved fortress town in Scandinavia and one of the most intact examples of Baroque military architecture in northern Europe. Enclosed by wide earthen ramparts, a moat, and angular bastions designed according to the latest Dutch engineering principles of the 17th century, it sits on the west bank of the Glomma, looking across to the newer town. The fortifications were built and extended between 1663 and 1779, and the layout you walk today is essentially as it was when garrisons trained on the parade ground and cannons guarded the river approach.
What makes Gamlebyen exceptional is that it remains a living place. Around 350 people live inside the old walls in low wooden houses painted in muted reds and yellows. There are craft workshops, restaurants, a church, and a local museum. In summer the cobbled streets fill with visitors but never feel overwhelmed — the scale is intimate, the atmosphere unhurried. Arrive on the small passenger ferry from the New Town quay and the effect is immediate: a five-minute boat trip that crosses several centuries.