Kiruna houses the largest underground mine (iron ore) in the world and is also known for the Satellite/Space projects, the Sámi culture, the long winters, the modern town planning, and the beautiful church and town hall.
At N67°49'48'' latitude, Kiruna is within the Arctic Circle, so it's possible to experience the midnight sun and polar night.
SAS has direct flights to Kiruna (also via Umeå) from Stockholm Arlanda.
From Stockholm, train travel is 16 hours.
Kiruna kyrkan (Kiruna Church) .
At the Esrange rocket-facility
The 17th century parish church.
Xero, . Zero-gravity flights on an Ilyushin 76MDK, used to train cosmonaunts. Book well in advance though, as these flights are only offered a few times a year and you get to fork out upwards of $8000 for the 90-min rollercoaster ride.
The nearby space-facility Esrange offers guided tours.