As of Monday, June 13, Queen Elizabeth II is the second-longest reigning monarch in world history, with 70 years and 127 days on the throne.

The queen, who began her reign in 1952 at age 25, has already surpassed her great-great-grandmother, Queen Victoria, as the monarch with the longest reign in British history. This month, the United Kingdom celebrated Queen Elizabeth II's 70-year rule with four days of celebrations honoring her service.

On Monday, according to BBC News, her reign surpassed that of Thailand's King Bhumibol Adulyadej, who ruled from 1946 until he died in 2016.

The only monarch ahead of Elizabeth in the record books is King Louis XIV of France. Louis became king at the age of four in 1643 and reigned until he died in 1715, a span of 72 years and 110 days. He began to reign personally in 1661, when he reached the age of majority.

According to the BBC, if Queen Elizabeth reigns for around two more years, until May 2024, she will surpass King Louis XIV as the longest-reigning monarch in history.

Elizabeth ascended to the throne upon her father's passing, King George VI, on February 6, 1952. The following year, at age 27, she was officially crowned in a coronation ceremony broadcast live on television for the first time, with about 27 million viewers in the United Kingdom alone.

As a princess, she was the first member of the royal family to serve as a full-time active military member during World War II. She learned how to drive and maintain vehicles while serving in the Auxiliary Territorial Service of the British Army.

She has met 13 of the 14 U.S. presidents that served during her reign, except President Lyndon B. Johnson.