A hundred years ago this month, Tokyo was flattened.

The Great Kanto Earthquake, a magnitude 7.9 event, demolished the nascent Japanese capital, killing more than 100,000 people — some 3% of the city’s population at the time.

For decades, the date has been marked in the country as Disaster Prevention Day — a reminder of the need for constant vigilance. The centenary will refocus that thought. To live in Tokyo is to be at once constantly aware of this threat, yet always pushing it to the back of one’s mind. Everyone knows the capital is at persistent risk of another disaster: The government estimates a 70% chance of a magnitude 7 event striking directly underneath the capital in the next 30 years.