Queen Elizabeth II has died.
The Queen was under medical supervision at Balmoral Castle in Scotland for hours and members of the royal family gathered at her bedside.
Britain's longest-reigning monarch has been planning for her succession for some time. Members of the royal family, including Charles, the longest-serving heir in British history, have increased their responsibilities as the queen's health has declined.
Q: Who will inherit the throne once Queen Elizabeth dies?
A: Charles, as the queen's eldest son, at the time of her death will inherit the sovereign title and job as head of the Commonwealth, along with other assets such as land and property.
In the past, the queen expressed desire for Charles to take over the Commonwealth.
"It is my sincere wish that the Commonwealth will continue to offer stability and continuity for future generations, and will decide that one day the Prince of Wales should carry on the important work started by my father in 1949," she said in 2018 after he was unanimously voted to be the next head.
Q: Who is Charles, Prince of Wales?
A: Charles, 73, has waited decades to become king and is the longest-serving heir in British history. He is the eldest of four children born to the queen and her late husband, Prince Philip. When his mother assumed the throne at age 25, he became Britain's heir apparent at age 3. Charles's titles include Prince of Wales, Duke of Cornwall, Duke of Rothesay and Earl of Carrick.
Charles married Diana Spencer in 1981 and the couple became known as the Prince and Princess of Wales. They had two children, Princes William and Harry. Charles and Diana separated in 1992. Following Diana's death in 1997, Charles remarried Camilla Parker Bowles, now known as the Duchess of Cornwall, in 2005.
Charles has long campaigned for a better environment, championing global sustainability in speeches over the years. His work includes expanding education and opportunities for young people in the United Kingdom.
Q: Will he be King Charles III?
A: Not necessarily. His full name is Charles Philip Arthur George, so he could select any of those as his regnal title. This means that Britain's next monarch might not go by the name of Charles, or he could decide he wants to be referred to as King Philip or King Arthur.
Q: Does that mean Camilla will be queen?
A: Usually, the wife of a king assumes the title of queen, however in Camilla's case this may not be as straightforward.
An agreement was made in 2005, at the time of Charles and Camilla's wedding, that she would not be known as queen, but as princess consort - although once he is on the throne, Charles can change her title to queen if he wishes.
Q: Who is next in line after Charles?
A: After Charles is his elder son, William, 40, known as the Duke of Cambridge. Next in line is William's eldest child, Prince George, who is 9; and then Princess Charlotte, 7; and Prince Louis, 4.
Q: Where is Prince Harry in all this?
A: Harry remains in the order of succession and is sixth in line to the throne, despite a controversial decision to step back from royal duties and move to the United States with his wife Meghan, where they live with their two children, Archie and Lilibet.
Q: Is Prince Andrew still in line?
A: Andrew, Duke of York is ninth in line to the British throne. He is the second son of the queen but announced in 2019 that he would be quitting public duties after becoming enmeshed in a sex abuse lawsuit filed by an American woman who said disgraced financier Jeffrey Epstein forced her to have sex with the prince on three occasions.
As Andrew is so far down the line of succession it is unlikely he would ever be king. Further, British media has long reported that Charles is mulling the idea of a slim-downed monarchy and will likely reduce the number of family members considered senior royals - which could mean Andrew's role is cut.
Q: How does the order of succession change?
A: The line of succession is fluid and the sequence often changes. Royals can move up or down a place whenever a member dies, abdicates or when a new baby is born.
Q: Why can't Prince William be king right away?
A: As the eldest son of Charles and the late Princess Diana, William is second in line to the British throne and is expected to one day become king. This will only happen when Charles dies or if he retires or abdicates - chooses to pass the crown to his son.
When the time comes for William to be crowned king, his wife Catherine, Duchess of Cambridge, will become queen consort. Their firstborn child, George, will likely inherit his father's dukedoms.
Q: How will William's life change once Charles is king?
A: William is expected to inherit the title Duke of Cornwall, which is one of many held by Charles.
On becoming the Duke of Cornwall, William will inherit the Duchy of Cornwall (an estate of 150,000 acres, with a yearly income of around 20 million pounds ($27 million U.S. dollars).
Q: Could a toddler become king or queen?
A: Half of the royals waiting in line to the throne are children. Prince George, age 9, is third in line to the throne after his father.
Regulation states that a person of any age can become monarch but children are not permitted to carry out duties until they reach the age of 18. Therefore, if it came to it, George would serve as a "symbolic" king until he is considered an adult, with a prince or princess regent who is in line and over the age of 18 ruling in his place.