Helsinki: Shelters for a Million People in Case of Nuclear Threat

Beneath Helsinki is a vast network of shelters capable of accommodating nearly a million people in the event of a nuclear strike. Finland began constructing these facilities after the Soviet invasion during the Winter War, and a law from 1954 mandates shelters under large buildings. One of the largest shelters is the 'Merihaka' complex, which can be repurposed for emergencies and serves as a sports center during peacetime.