75 years ago, pilot Kenneth Arnold sighted several strange objects in the sky near Washington's Mount Rainier.
Known for his 'out there' alien theories, Tsoukalos started his career very differently.
Prof Don Arnold and colleagues have been attempting to solve the long-running mystery of where our memories are stored.
The UK public have picked the Terminator himself - Arnold Schwarzenegger - to protect them from aliens.
A tiny fly with very strong forelegs has been named after one of the world's most famous bodybuilders.
Amateur pilot Kenneth Arnold kick-started the modern UFO phenomenon after a sighting back in 1947.