theropod dinosaurs, and 1930s forgeries. Yonaguni Monument: An unusual underwater rock formation near the southern Ryukyu Islands, was considered a man-made monolith because of the even cracks. Bosnian pyramid complex: Unproven claim that there is a pyramid complex in the vicinity of town of Visoko in Bosnia. Erroneously dated objects Aiud object: An aluminum wedge found in 1974 in the Mureș River in central Romania, near the town of Aiud; it has been claimed by Romanian UFOlogists to be of ancient and/or extraterrestrial origin, yet it is more likely a fragment of modern machinery lost during excavation work. Coso artifact: Claimed to be prehistoric; actually a 1920s spark plug. Malachite Man: Thought to be from the early Cretaceous; actually a post-Columbian burial. Nampa figurine: Was a clay fired doll found in Nampa, Idaho during a well drilling. Early dating attempts believed the artifact to be 2 million years old due to the rock layer it was found in. Later assessments found that the artifact was either only a few thousand years old or a 19th century Native American doll. Many have criticized the object as a likely hoax. Wolfsegg Iron: Thought to be from the Tertiary epoch; actually from an early mining operation. Inaccurately described as a perfect cube. Modern-day creations, forgeries and hoaxes Babylonokia: A clay tablet shaped like a mobile phone and created as an artwork in 2012. Fringe scientists and alternative archaeology proponents subsequently misrepresented a photograph of the artwork as showing an 800-year-old archaeological find. The story was popularised in a video on the YouTube channel Paranormal Crucible and led to the object being reported by some press sources as a mystery. Acámbaro figures: Mid-20th-century figurines of dinosaurs, attributed by Waldemar Julsrud to an ancient society. Calaveras Skull: A human skull found by miners in Calaveras County, California, which was purported to prove that humans, mastodons, and elephants had coexisted in prehistoric California. It was later revealed to be a hoax. Cardiff Giant: A 19th-century hoax of a ten-foot-tall supposedly petrified man exhibited as a giant from biblical times. Quickly debunked by experts, and by the confession of the forger, it was nonetheless a popular marvel of the day. Crystal skulls: Supposedly demonstrate more advanced stone-cutting skill than was previously known from pre-Columbian Mesoamerica. Appear to have been made in the 19th century. Gosford Glyphs: A collection of Egyptian hieroglyphs in Central Coast, Australia, that have