Deep in central south Australia in an area not easily accessible by roads is the largest known geoglyph on the planet. It is called the Marree Man and it is just over 2.6 miles long. It was discovered during a flyover in 1998.
Shortly after that many outlets received press releases from the apparent creator who remained anonymous.
Based on several word used in the press releases, some people concluded that the marree man was made by an American.