President Donald Trump turns 73 today. Two of his leading challengers, Mr Joe Biden and Mr Bernie Sanders, are 76 and 77, respectively. A third, Ms Elizabeth Warren, turns 70 on June 22.
"I just feel like a young man," Mr Trump told reporters on the White House lawn in April. "I'm so young. I can't believe it. I'm the youngest person. I am a young, vibrant man."