Tuesday marks the 10th anniversary of the worst tragedy in recent South Korean history: the sinking of the Sewol passenger ferry off the country’s southwest coast. The disaster claimed the lives of more than 300 people — the vast majority high school students on a field trip — and deeply damaged public trust in the government, setting off a series of events that brought down the president three years later.

It has also been one of the single most common topics in North Korean state media over the past decade.