Emmanuel Macron, 39, will join the ranks of the world's youngest leaders when he is inaugurated as president of France on Sunday.
Some leaders past and president who made big marks were even younger when they assumed power.
The Cuban revolutionary leader, who died last year, was 32 when his rebel forces took control of Cuba. He ruled for nearly five decades as one of the world's last communist leaders.
John F. Kennedy
Kennedy was the youngest person ever elected to the presidency of the United States. The wealthy senator and war hero was 43 when he took the oath of office in 1961. But he was not the youngest U.S. president ever — that was Theodore Roosevelt, who was 42 when he took over after the assassination of President William McKinley.
Tony Blair and David Cameron
Blair was 43 when he was elected Britain's prime minister in 1997 — the country's youngest leader since 42-year-old Lord Liverpool in 1812.
Cameron was also 43, but a few months younger than Blair, when he became Britain's leader in 2010.
Mustafa Kemal Ataturk
Ataturk, the revered founder of the Republic of Turkey, was 42 when he became the country's first president in 1923. The revolutionary leader's last name means "Father of the Turks.''
Sigmundur David Gunnlaugsson
In Iceland, Gunnlaugsson became prime minister at 38 in 2013. He resigned in 2016 after details of his offshore financial holdings were revealed in the Panama Papers leak.
The late Libyan leader was 27 when he seized power in 1969. The dictator held on to power until he was ousted in 2011. He was captured and killed a few months later.
Gamal Abdel Nasser
Nasser was 38 when he became president of Egypt in 1956. He nationalized the Suez Canal and championed the pan-Arab cause, becoming one of the world's most prominent anti-imperialist figures by the time of his death in 1970.
Kim Jong Un
The North Korean ruler's age remains something of a mystery, but he is thought to be 32 or 33. Kim, the third generation in North Korea's ruling dynasty, assumed power in December 2011 upon the death of his father, Kim Jong Il.
Gandhi was catapulted to India's highest office when his mother, Prime Minister Indira Gandhi, was assassinated in 1984. He began his premiership with promises of modernizing India's creaking government. Within a few years, he was forced to resign amid allegations of taking bribes in an arms deal. He was assassinated in 1991 while campaigning to return to office.
Trudeau was elected as Canada's prime minister in 2015, when he was 43. Like Rajiv Gandhi, he had a strong family connection to the office — his father, Pierre Trudeau, also served as prime minister.