Meaning: All people without exception experienced enjoyment or amusement at a public area with trees, grass, and other features for recreation.
Choice of Words: The word "everyone" refers to all people without exception. "Had" means possessed or owned something. "Fun" refers to enjoyment or amusement. "At" indicates the location where the enjoyment or amusement took place. "Park" refers to a public area with trees, grass, and other features for recreation.