It was the biggest intelligence breach in U.S. history – the leaking of more than a half-million classified documents on the WikiLeaks website in the spring of 2010. Behind it all stood two very different individuals: Julian Assange, the Internet activist and hacker who published the documents, and an Army intelligence analyst named Chelsea Manning, who was charged with handing them over. FRONTLINE tells the full story behind the leaks and reports on the U.S. government’s struggle to protect national security information in a post-9/11 world. Explore more stories on the original website for WikiSecrets.

(Editor’s note: As WikiSecrets was produced before Manning announced her transition, she is referred to as Bradley and with male pronouns throughout the documentary.)