But the disaster sent a cloud of radioactive fallout over hundreds of thousands of square miles of what is now Russia, Belarus and Ukraine that would have an impact on the health of many more.

CNN: 26 years on: helping Chernobyl's children

That is why they drove straight into the radioactive cloud.

ECONOMIST: Banyan

In 1986, the fourth reactor at the Chernobyl nuclear complex in the Ukraine exploded and caught fire, spreading a radioactive cloud across Europe in the world's worst nuclear disaster.

CNN: Saturday,

The positrons, produced by the decay of radioactive sodium, are cooled into a similarly sized cloud of around 1m particles and held in a neighbouring trap.

ECONOMIST: Antihydrogen atoms are captured for the first time