The Fifth Avenue Mile is like a really special race that happens on Fifth Avenue in New York City. A bunch of grown-ups who really like to run and be healthy get together and race each other to see who is the fastest.
They get all dressed up in special running clothes and line up at the starting line. They have to run one mile, which is like running around a really big track four times. They run as fast as they can and try to cross the finish line before anyone else.
Lots of people come to watch and cheer for the runners. They clap and yell and wave flags and stuff to encourage them. It's really fun to watch!
At the end of the race, the runners get special prizes and medals. Everyone is really proud of themselves, even if they didn't win, because they tried their best and did something really good for their body.