Britain’s national treasure and veteran naturalist, Sir David Attenborough, is 91-years-old-today. The highly celebrated and much-loved writer, broadcaster and wildlife presenter has graced the screens of adoring fans for more than six decades. But where did his passion for wildlife and conservation begin?

Born to a University lecturer and principal in 1926, Sir David became enchanted by the natural world at a very early age. By the time he had reached the tender age of 7-years-old, he had amassed a substantial collection of fossils. Attenborough’s fascination with nature continued, earning him a scholarship to study the Natural Sciences at Cambridge University.

After graduation in 1947, the Cambridge graduate was conscripted into the Royal Navy and posted to Wales. When his National Service was complete, Attenborough embarked on a training program with the BBC, the beginning of a monumental career.

At the time, the BBC devoted neither money or resources to the natural sciences, and his physical appearance, namely the size of his teeth, were deemed too big for a TV presenter. Although Mr. Attenborough eventually produced two TV shows; the Pattern of Animals and Animal, Vegetable and Mineral? He was irked by the way in which animals were portrayed in captivity, notably TV studios.

A young David Attenborough Featured image credit: Keystone Getty I

By 1954, Sir David had convinced BBC executives that filming animals in the wild was the way forward. Subsequently, he launched the TV series, Zoo Quest. Filming on location and in a non-intrusive way, the show became a roaring success, prompting the BBC to establish its Natural History Unit.

Attenborough left the BBC briefly to study social anthropology but returned in 1965 as both a programmer and controller. At the time, the broadcaster was transitioning to color television. Sir David left the BBC again in 1972, this time to follow his great passions: anthropology and producing wildlife documentaries.

As a freelancer, Attenborough was successful, but by far his greatest success came in 1976, when TV show Life on Earth, first aired. Spanning more than 90 episodes, the series took David Attenborough and his production team to almost every continent. Sir David became a regular fixture on the TV screens of homes around the globe. Nonetheless, Attenborough refused to take all the credit for the highly successful series, instead, crediting his film crew for their expertise.

“Cameramen are among the most extraordinarily able and competent people I know. They have to have an insight into natural history that gives them a sixth sense of what the creature is going to do, so they can be ready to follow.”

More than 400 million viewers tuned into Life on Earth. The iconic series was the first of many similar documentaries, written, produced and narrated by the celebrated TV personality. In 1995, Attenborough produced The Private Life of Plants. In many ways, the production was groundbreaking in that it used time time-lapse photography.

In 2006, however, came Planet Earth, the largest of all BBC’s natural science productions regarding funding and resources. The series took five years to produce, and within three months of the first airing, had been shown in more than a 120 countries. Planet Earth was also the first of the BBC’s filming in high definition. The first five episodes drew more than 11 million viewers.

The sprightly 91-year-old has made no plans to retire and is currently working on Blue Planet ll, the sequel to the 2001 production. Modest as ever, Sir David has remained gracious despite his phenomenal success.

Speaking to the Observer last year, Attenborough mocked the idea of being considered a national treasure.

“What does ‘national treasure’ mean?” he replies, with a twinkle in his eye. “Nothing, except that people are favourably disposed towards you. You’re not being elected. You haven’t got the power to become prime minister. The problem is that you are credited with more wisdom and apprehension than is the case – which is quite easy actually. People think you know everything, but of course you don’t!

Fans of Sir David tweeted birthday messages on Twitter today.

Happy Birthday Sir David Attenborough! He's 91 today - so here are his birthday best bits ???? pic.twitter.com/bVZVogBVuL — BBC Newsbeat (@BBCNewsbeat) May 8, 2017

We don't normally promote rival talent but today is an exception. A huge happy birthday to David Attenborough. Thanks for everything, Sir. pic.twitter.com/SxVx7YuABE — ITV (@ITV) May 8, 2017

David Attenborough is 91 today, Happy Birthday David! pic.twitter.com/uXFWFA8cCQ — Classic British TV (@Classicbritcom) May 7, 2017

The moment when Sir David Attenborough got upstaged by a bird... ????

Happy birthday Sir David! ???? ???? pic.twitter.com/Rg06Jrax3v — BBC Two (@BBCTwo) May 8, 2017

[Featured Image by Peter Macdiarmid/Getty Images]