As Japan works to prevent a meltdown at its earthquake-hit Fukushima-Daiichi nuclear plant, Ukraine is preparing to mark the 25th anniversary of the world’s worst nuclear accident. The legacy of the meltdown at the Chernobyl plant includes a 30-km uninhabited ring around the site of the meltdown, billions of dollars spent cleaning the region, and a major new effort to raise US $840 million in funds that Kiev needs to build a more durable casement over the stricken reactor. Psychological and physical scars persist, too. Studies have found that “exposed populations had anxiety levels that were twice as high” as people unaffected by the accident, as well as a “dramatic increase in thyroid cancer incidence” in the Ukraine and just across the border in Belarus. But there are differences between Chernobyl and the disaster in Japan. Chernobyl was the product of human error, while the Japanese failure was triggered by an earthquake and tsunami. Chernobyl occurred in a secretive Soviet society, and authorities attempted to cover-up the truth until three days after it occurred, which delayed international aid. Most notably, thick containment walls at the Fukushima Daiichi plant shielded the reactor cores so that even if there was a meltdown, it’s unlikely to lead to a major escape of dangerous radioactive clouds into the atmosphere. Chernobyl had no such structure.