Finland is testing how communities could survive a major crisis underground.

Inside Luola, one of Europe's most advanced civil defense shelters, more than 2,000 people joined a large-scale preparedness exercise to see whether daily life can continue during emergencies.

The drill examined everything from drinking water and sleeping arrangements to the psychological challenges of confinement.

Shaped by history, geography and proximity to Russia, Finland's culture of preparedness extends beyond war to cyberattacks, disinformation and other hybrid threats, with a nationwide network of shelters designed to protect most of the population.