In 1927, Al Jolson received a standing ovation when he spoke the first words ever heard in a feature film. "Wait a minute, wait a minute," he said. "You ain't heard nothin' yet!" And they hadn't.
However, sight and sound were still only two-fifths of the package, and 80 years on we are barely any closer to the all-enveloping "feelies" envisaged by Aldous Huxley in his novel Brave New World. Not that it's been for the want of trying. And one sense - that of smell - has received more than its fair share of attention from inventors.
By 1959, Hollywood was facing serious competition from television. So, in an attempt to give cinema audiences something extra, one studio offered them AromaRama. It made its debut in The Great Wall - a travelogue of China - which featured a palette of supposedly oriental odours and the slogan:
"You must breathe it to believe it!"
The smells were pumped out through the cinema's air conditioning system, but by the time they reached the back rows, they were completely out of sync with the action.
Two months later, however, a film called Scent Of Mystery seemed to offer fresh hope to the purveyors of pong. It used a more sophisticated set-up called Smell-O-Vision, a Swiss invention that delivered 30 different fragrances directly to each seat via a network of plastic tubes.
But for all its sophistication, Smell-O-Vision turned out to be another disaster - not least because it proved impossible to clear the auditorium of the accumulated vapours.
By the end of the show, the place reeked of a mixture of garlic, pipe smoke and shoe polish, leaving audiences gasping for fresh air.
Many years later, Scent Of Mystery was re-released under the title Holiday In Spain, without the slightest hint of odour, and audiences were left holding their breath in anticipation of the 1980s scratch'n'sniff card.