World's Smallest Park
Portland, Oregon
In 1946 a traffic median was built along what is now Naito Parkway in downtown Portland. One small section had a post hole for a stoplight pole, but for some reason the pole was never installed. Dick Fagan, a columnist for the Oregon Journal, noticed the hole from his office window. He decided to replace the weeds and trash that filled the hole with flowers, and christened it Mill Ends Park (not "Mill's End") on March 17, 1948 -- an early example of Portland weirdness. The park has outlived both Fagan and the Oregon Journal; it was recognized by Guinness World Records as the World's Smallest Park -- 452 square inches -- in 1971, and named an official Portland city park in 1976.
In March 2013 someone dug up and stole the park's one little tree, but must have felt guilty because the tree was returned the next day.
Depending on the timing of your visit, you may or may not see a tiny tree in Mill Ends Park; the city replaces it every few months.