Queen of Firsts: How Elizabeth II changed the monarchy

Queen Elizabeth's 70 years on the throne made her the longest reigning monarch in British history, and over that time she transformed the royal family forever.

For seven decades, she made and witnessed history as head of the royal family

In 2015, she became the longest reigning monarch in British history, outpacing her great-great-grandmother Queen Victoria and her 63 years of service on the throne.

But Elizabeth II was queen of many other firsts.

Her coronation ceremony in 1953 was watched by a record 27 million people in the UK alone and was the first to be broadcast on television.

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Her Majesty started the tradition of her famous royal "walkabouts," which started when she greeted the public in 1970 during a tour in Sydney.

The most traveled of any of her British predecessors, the Queen visited over 100 countries on behalf of the crown, including the first state visit to then West Germany in 1965.

Then, 21 years later, widely seen as one of her most historic tours and a critical act of diplomacy at the time, she became the first British monarch to visit China in 1986.

She was also the first to address the U.S. Congress in 1991.

"Force, in the end, is sterile. We have gone a better way: our societies rest on mutual agreement, on contract and on consensus," the Queen said.

Another historic first came in May 2011 when she became the first to visit the Republic of Ireland by a British monarch in 100 years.

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It was the first time a reigning monarch traveled to the "Emerald Isle" since its separation from the United Kingdom.

"That moment when she came off the airplane in Ireland, the republic, and came down the steps dressed in Saint Patrick's blue, and later on, lowered her head at the memorial to those who had sought republican success and who had fought for it, that was significant. I think the Queen was trying to create an environment for an improvement in relations," said ABC News royal contributor, Alastair Bruce.

"To all those who have suffered as a consequence of our troubled past, I extend my sincere thoughts and deep sympathy. With the benefit of historical hindsight, we can all see things which we would wish had been done differently or not at all," the Queen said at the time.

Then, this past summer Her Majesty was the first British monarch to celebrate a Platinum Jubilee, a four day celebration marking 70 years on the throne.