Sydney Harbour Bridge was once home to 'world famous' cats

In the 1950s Australia was a vastly different place.

Colour television had just arrived on our shores, pop music was gaining notoriety, and cats lived inside the Sydney Harbour Bridge.

For nearly two decades an ever-growing family of felines called the south-east pylon home, making the "world-famous" cats one of the lookout's biggest drawcards.

The animals were cared for by Yvonne Rentoul, who in 1948 leased the pylon from the Department of Main Roads and turned it into an "educational" tourist attraction.

She called it her All Australian Exhibition and was adamant it was not a museum.

"It is educational because we have arranged dioramas showing different aspects of Australian life," Mrs Rentoul told The Daily Telegraph.

In the years before WWII the lookout had operated as a "fun house", but it was reclaimed by the government in 1942 to make room for an anti-aircraft gun and its crew.

In another article in The Daily Telegraph, Mrs Rentoul was described as "a soft-spoken, vivacious brunette"

She told the publication it was "outrageous" to let a pylon, located in a prime position on Sydney's glistening harbour go to waste.

So, inside the lookout she constructed a diorama, a tribute to the Royal Australian Navy, a "penthouse", a cafe, and a souvenir shop, according to Museums Victoria.

One of the first mentions of the cats comes in an article published in The Sunday Herald on July 29, 1951.

Named Bridget and Pylon, the white pets were reported to be twin sisters.

"If one cat wants to pass the other, she risks death by leaping over her twin's back," an extract explained.

"Even in wet weather Bridget and Pylon never leave their lofty home.

"Since they took up residence on top of the pylon, one of the twins, Pylon, has never been downstairs.

"Bridget was once carried down but as soon as she was released she raced up again and has stayed there ever since."

From then the cats gained popularity.

Mrs Rentoul built a rooftop cattery for her companions, and a brochure advertising the pylon as a tourist destination deemed the white cats "world-famous".

"A joy for the kiddies and a delight for adults," the pamphlet boasted.

"They are unique, they even have their own merry-go-round!".

Photographs from the time show the cats enjoying the high life, and tiptoeing across barriers nearly 100 metres above ground.

More than 60 cats are thought to have called the southeast pylon home over the 21 years Mrs Rentoul ran her shop from it.

When she retired she took the remaining cats home with her.