Why is "Boden Fortress" trending?

Wikipedia Overview

Boden Fortress is a modern fortress consisting of several major and minor forts and fortifications surrounding the city of Boden, Norrbotten, in northern Sweden. The fortress was originally intended to stop or delay attacks from the east or coastal assaults, which at the time of construction meant Russian attacks launched from Finland. It was primarily the expansion of the railway network in Norrland, which in turn was a consequence of the rising importance of the northern iron ore fields, that led to the increased strategic value of northern Sweden and the construction of the fortress. Although the main forts were finished in 1908, many of the supporting fortifications were not completed until the start of the First World War. Improvements were also continuously made during, and between, both World Wars.