They built their bomb in secret, under the cover of a peaceful nuclear reactor. After aerial photographs caught them constructing a massive plutonium plant in the desert, they claimed it was just a research laboratory. Under US pressure, they let American inspectors in, but managed to conceal for years what they were really doing.
This may sound like the history of Iran’s nuclear program, but it’s not. It’s the story of Dimona, Israel’s plutonium complex built in the late 1950s with French assistance.