James Randi

The Canadian-American stage magician famously offered a one-million-dollar prize to anyone who could prove paranormal abilities under agreed-upon scientific testing conditions. The prize was famously never claimed before it was retired.

Randi founded the James Randi Educational Foundation (JREF). The organization was dedicated to promoting critical thinking and exposing pseudoscientific claims to the public.

Yes, he famously exposed faith healer Peter Popoff by secretly recording the radio transmissions Popoff's wife used to feed him audience information. He was also a prominent public critic of Uri Geller's alleged psychic spoon-bending.

Early in his career, he performed under the stage name The Amazing Randi. He was a skilled escapologist who often drew comparisons to Harry Houdini for his daring escapes and his later crusade against frauds.