Tromsø

Tromsø needs 3 days: a nighttime excursion chasing the northern lights, with guides tracking clear skies around the region, on one, the Fjellheisen cable car up Mount Storsteinen for views over the city on another, and a husky dog sledding trip on the third. September-March brings aurora season; May-July, by contrast, brings the midnight sun. It's expensive, with aurora and sledding excursions as the main cost. It's 350 km north of the Arctic Circle and one of the largest cities in the world at that latitude, nicknamed the «Gateway to the Arctic» for being the historic starting point of polar expeditions to both the Arctic and Antarctica.