The newly-crowned king and queen departed in style from Westminster Abbey to travel back to Buckingham Palace in the Coronation Procession.

Their Majesties rode in the Gold State Coach, which has been used at every coronation since 1831.

The public last saw the Gold State Coach at the queen’s Platinum Jubilee celebration last year.

The congregation and choir join in singing the National Anthem as Charles and Camilla process out of Westminster Abbey.

The Robe of Estate worn by Charles was also worn by his grandfather King George VI in 1937. It is made of purple silk velvet and is embroidered in gold.

Camilla’s purple velvet Robe of Estate was designed and created for her by the Royal School of Needlework, of which she is patron. The design features hand-embroidered plants and insects, which were included to reflect her and Charles’ love of nature.

As the proclamation "long live the king" rang out in Westminster Abbey, it was a very different atmosphere in Trafalgar Square -- hundreds of protesters booed loudly and chanted "not my king."

The protesters have been there since the morning and were mixed among royals fans. Yellow banners reading "Abolish the Monarchy" waved in the air, dueling with the Union Jack flags held by people celebrating the coronation.

It's rare to see an anti-royal demonstration in the United Kingdom. The number of people who gathered in support of the crown far outnumbered those who were protesting. However, the issues that motivate the protesters, such as the monarchy being out of date and linked to colonialism, are ones that present serious challenges that Charles will immediately face in trying to keep the crown relevant.

Among those challenges that will emerge immediately are countries in the British Commonwealth that are seeking to remove Charles as head of state. Jamaica has signaled its plans to do so soon and there are questions whether Australia could follow in the coming years.

-ABC News' Patrick Reevell

As the choir sings hymns composed for past coronations, Charles and Camilla enter the Shrine of St Edward the Confessor.

As they depart, Charles is wearing the Imperial State Crown, while Camilla is wearing the St. Mary’s Crown.

The Imperial State Crown was made in 1937 for the coronation of Charles’ grandfather. It contains 2,868 diamonds, 17 sapphires, 11 emeralds, 269 pearls and four rubies.

Charles will wear the crown again on occasions like the state opening of Parliament.
The crown was last seen publicly atop the coffin of Queen Elizabeth II.