The smallest park in the world is Mill Ends Park in Portland, Oregon. It is 452 square inches or barely two feet across and not quite suitable for a barbecue. The nearby Forest Park is 60 million times as big.
Mill Ends started in 1948, when Oregon Journal journalist Dick Fagan
noticed a forgotten hole outside his office on Front Street. He
planted flowers and began to write a weekly column about goings-on
When Fagan died in 1969, Portland took up the tradition and
dedicated Mill Ends as an official city park in 1976. Sometimes it
has a swimming pool for butterflies, with diving board, a miniature
Ferris wheel, and statues. It hosts snail races, weddings, and
regular rose plantings.