The spy who changed history and a great-aunt’s double life. In season one we met the scientist who might have stopped the atomic bomb. In season two we meet the man who stole it.

In The Bomb, a new podcast from the BBC World Service, the American writer and journalist Emily Strasser recalls a photograph in her grandmother’s house near Oak Ridge, Tennessee, which showed her grandfather standing in front of a mushroom cloud. During the second world war, George Strasser had worked at a secret facility devoted to uranium enrichment alongside thousands of other employees. Before the plant was built, the town didn’t exist.

Strasser traces the atomic bomb’s creation back to Leo Szilard, a Hungarian physicist and a close friend of Albert Einstein who lived in Berlin in the 1920s. In 1933, noting the growing hostility towards Jews, he left Germany for London. There he had a scientific epiphany about the possibility of a nuclear chain reaction and, after relocating to the US, watched it become reality via Chicago Pile-1, the world’s first artificial nuclear reactor. But, as Strasser reports, Szilard was concerned about the destruction that could be wrought with nuclear weapons and what could happen if they ended up in enemy hands. After the attacks on Japan, she says, “he was haunted by the bomb for the rest of his life.”