1) Tokyo-Yokohama, Japan: With 37 million inhabitants living under the threat of earthquakes, monsoons, river floods and tsunami, the Tokyo-Yokohama region is by far the riskiest in the world: an estimated 80% of Tokyoites, or 29 million, are potentially exposed at any one time to a very large earthquake. Japan is also the country most exposed to tsunami risk, as the country’s urban centres are dotted with an almost perverse accuracy along the Ring of Fire, the active faults of the western Pacific. The Great Kanto Earthquake of 1923 devastated both Tokyo and Yokohama, killing an estimated 142,800 people.(A note on the methodology of the Swiss Re report: residents threatened by multiple perils are counted more than once in the statistics. So the total number of people potentially affected by multiple perils can therefore exceed the size of a city’s population.)