Sweden has 65,000 bunkers. Here's why it's building even more.
Burrowed beneath a small park in Stockholm is a forgotten relic of the past that may help in the future. The only clue to its existence is a green metal door, 8 feet high by 5 feet wide, hewn into the rock next to a busy, snow-dusted sidewalk. Heaving it open reveals an airlock that leads to a fully operational nuclear bunker. Facilities like this are a vital part of Sweden's history — and recent threats from Russia mean they could become important again in the years to come.