Queen Elizabeth updates: State funeral ends 11 days of ceremonies

King Charles III wants to protect the planet for future generations -- a passion he has highlighted throughout his decades as monarch-in-waiting.

Now, Charles ascends the throne as the longest-serving Prince of Wales in British history. And in those six decades, he not only voiced his concerns about the destructive processes that are harming the Earth but implemented sustainable, organic practices in his own homes.

"His mother took the crown at a very young age, and nobody knew what she stood for," David Victor, a professor of innovation and public policy at the University of California at San Diego's School of Global Policy and Strategy and author of "Fixing the Climate: Strategies for an Uncertain World," told ABC News. "Whereas he is taking the crown very late in age, and everybody knows what he stands for -- and for a whole range of topics."

A royal guard apparently fainted as he watched over the coffin holding the late Queen Elizabeth II at London's Westminster Hall.

The incident was captured on BBC News' live streaming broadcast early Thursday at around 1 a.m. local time. A guard, who was standing at the foot of the coffin, appeared to faint and fall to the ground.

BBC suspended its livestream following the incident.

Guards clad in ceremonial uniform are maintaining a 24-hour vigil around the coffin inside Westminster Hall.

The doors of Westminster Hall have now been opened to the public to allow people to pay their respects to the late Queen Elizabeth as she lies in state.

Lines have been forming for the last 24 hours as Londoners hope to get the chance to walk by the queen's casket.

The last member of the royal family to lie in state at Westminster Hall was Queen Elizabeth’s mother, who died in 2002.

President Joe Biden spoke Wednesday with King Charles III to offer his condolences, according to a statement from the White House.

Biden hopes "to continue a close relationship with the King," the statement said.

"The President recalled fondly the Queen’s kindness and hospitality, including when she hosted him and the First Lady at Windsor Castle last June,” the statement said. "He also conveyed the great admiration of the American people for the Queen, whose dignity and constancy deepened the enduring friendship and special relationship between the United States and the United Kingdom."