A freak show is an exhibition of biological rarities, referred to in popular culture as "freaks of nature". Typical features would be physically unusual humans, such as those uncommonly large or small, those with extraordinary diseases and conditions, and others with performances expected to be shocking to viewers. Heavily tattooed or pierced people have sometimes been seen in freak shows (more common in modern times as a sideshow act), as have attention-getting physical performers such as fire-eating and sword-swallowing acts.

History Since at latest the medieval period, people with deformities have often been treated as objects of interest and entertainment, and crowds have flocked to see them exhibited.Drimmer, Frederick (1985). Very Special People: the Struggles, Loves, and Triumphs of Human Oddities. New York: Bell Publishing Co. p. xiii. A famous early modern example was the exhibition at the court of King Charles I of Lazarus and Joannes Baptista Colloredo, two conjoined brothers born in Genoa, Italy. While Lazarus appeared to be otherwise ordinary, the underdeveloped body of his brother dangled from his chest. When Lazarus was not exhibiting himself, he covered his brother with his cloak to avoid unnecessary attention.Bondeson, Jan. (2000) The Two-Headed Boy, and Other Medical Marvels

As well as exhibitions, freak shows were popular in the taverns and fairgrounds, where the freaks were often combined with talent displays. For example, in the 18th century, Matthias Buchinger, born without arms or lower legs, entertained crowds with astonishing displays of magic and musical ability, both in England and later, Ireland.

It was in the 19th century, both in the United States and Europe, where freak shows finally reached maturity as successful commercially run enterprises.

During the late 19th and early 20th centuries, freak shows were at their height of popularity; the period 1840s through to the 1940s saw the organized for-profit exhibition of people with physical, mental, or behavioral rarities. Although not all abnormalities were real, some being alleged, the exploitation for profit was seen as an accepted part of American culture. The attractiveness of freak shows led to the spread of the shows that were commonly seen at amusement parks, circuses, dime museums and vaudeville. The early amusement park industry flourished in the United States by the expanding middle class who benefited from short work weeks and a larger income. There was also a shift in American culture that influenced people to see leisure activities as a necessary and beneficial equivalent to working, thus leading to the popularity of the freak show.

The showmen and promoters exhibited all types of freaks. People who appeared or were non-white or who had a disability were often exhibited as unknown races and cultures. These "unknown" races and disabled whites were advertised as being undiscovered humans to attract viewers. For example, those with microcephaly, a condition linked to intellectual disabilities and characterized by a very small, pointed head and small overall structure, were considered or characterized as "missing links" or as atavistic specimens of an extinct race. Hypopituitary dwarfs who tend to be well proportioned were advertised as lofty. Achondroplastic dwarfs, whose head and limbs tend to be out of proportion to their trunks, were characterized as exotic mode. Those who were missing some or all of their limbs were also characterized in the exotic mode as animal-people, such as "The Snake-Man", and "The Seal Man". There were four ways freak shows were produced and marketed. The first was the oral spiel or lecture. This featured a showman or professor who managed the presentation of the people or "freaks". The second was a printed advertisement, usually using long pamphlets and broadside or newspaper advertisement of the freak show. The third step included costuming, choreography, performance, and space used to display the show, designed to emphasize the things that were considered abnormal about each performer. The final stage was a collectable drawing or photograph that portrayed the group of freaks on stage for viewers to take home.R. G Thomson in Freakery The cultural specatcle of the extraordinary body The collectable printed souvenirs were accompanied by recordings of the showman's pitch, the lecturer's yarn, and the professor's exaggerated accounts of what was witnessed at the show. Exhibits were authenticated by doctors who used medical terms that many could not comprehend at the time but which added an air of authenticity to the proceedings. Freak show culture normalized a specific way of thinking about gender, race, sexual aberrance, ethnicity, and disability. In the late 1920s and early 1930s, photographer Edward J. Kelty traveled with circus shows and took large group photos of the performers, including the "Congress of Freaks" portraits featuring acts the Ringling Brothers and Barnum & Bailey circus.

During the first decade of the 20th century, the popularity of the freak show was starting to dwindle. In their prime, freak shows had been the main attraction of the midway, but by 1940 they were starting to lose their audience, with credible people turning their backs on the show. The term ‘freak show’ has changed in connotation along with the change in attitudes as the public shifted from acceptance of performer exploitation to more concern and desire to understand them.  Although the term can often be insulting when used to describe a person, ‘freak show’ is still used in the modern circus to name a show that has performances involving extreme body modification, endurance, and other physical acts. In the 19th century, science supported and legitimized the growth of freak shows, but by the 20th century, the medicalization of human abnormalities contributed to the end of the exhibits' mystery and appeal.

P. T. Barnum P. T. Barnum was considered the father of modern-day advertising, and one of the most famous showmen and managers of the freak show industry. In the United States he was a major figure in popularizing the entertainment. However, it was common for Barnum's acts to be schemes and not altogether true. Although he spent years collecting specimens, artifacts, and displays, his main passion was showmanship and entertainment rather than scientific education.Dennett, Andrea Stulman. Weird and Wonderful: The Dime Museum in America. New York, NY: New York University Press, 1997. https://doi.org/10.18574/9780814744215.  Barnum was fully aware of the improper ethics behind his business as he said, "I don't believe in duping the public, but I believe in first attracting and then pleasing them." During the 1840s Barnum began his museum, which had a constantly rotating acts schedule, which included obese people, "living skeletons" (men who appear emaciated), little people, giants, and other people deemed to be freaks. The museum drew in about 400,000 visitors a year.Zachary Crockett, "The Rise and Fall of Circus Freakshows", "Priceonomics", June 28, 2016

Barnum's American Museum was one of the most popular museums in New York City to exhibit freaks. In 1841 Barnum purchased The American Museum, which made freaks the major attraction, following mainstream America in the mid-19th century. Barnum was known to advertise aggressively and make up outlandish stories about his exhibits. The façade of the museum was decorated with bright banners showcasing his attractions and included a band that performed outside. Barnum's American Museum also offered multiple attractions that not only entertained but tried to educate and uplift its working-class visitors. Barnum offered one ticket that guaranteed admission to his lectures, theatrical performances, a menagerie, and a glimpse at curiosities both living and dead.

One of Barnum's exhibits centered on Charles Sherwood Stratton, the dwarf billed as "General Tom Thumb" who was then 4 years of age but was stated to be 11. Charles had stopped growing after the first 6 months of his life, at which point he was 25 inches (64 cm) tall and weighed 15 pounds (6.8 kg). With heavy coaching and natural talent, the boy was taught to imitate people from Hercules to Napoleon. By 5, he was drinking wine, and by 7 smoking cigars for the public's amusement. During 1844–45, Barnum toured with Tom Thumb in Europe and met Queen Victoria, who was amusedQueen Victoria and Tom Thumb and saddened by the little man, and the event was a publicity coup. Barnum paid Stratton about $150.00 a week. When Stratton retired, he lived in the most esteemed neighborhood of New York, owned a yacht, and dressed in the nicest clothing he could buy.

In 1860, The American Museum had listed and archived thirteen human curiosities in the museum, including an albino family, The Living Aztecs, three dwarfs, a Black mother with two albino children, The Swiss Bearded Lady, and William Henry Johnson, an intellectually disabled Black man. Barnum introduced the "man-monkey" William Henry Johnson, a microcephalic Black dwarf who spoke a mysterious language created by Barnum and was known as Zip the Pinhead. In 1862, he discovered the giantess Anna Swan and Commodore Nutt, a new Tom Thumb, with whom Barnum visited President Abraham Lincoln at the White House. During the Civil War, Barnum's museum drew large audiences seeking diversion from the conflict.

Barnum's most popular and highest grossing act was the Tattooed Man, George Costentenus. He claimed to be a Greek-Albanian prince raised in a Turkish harem. He had 338 tattoos covering his body. Each one was ornate and told a story. His story was that he was on a military expedition but was captured by native people, who gave him the choice of either being chopped up into little pieces or receive full body tattoos. This process supposedly took three months and Costentenus was the only hostage who survived. He produced a 23-page book, which detailed every aspect of his experience and drew a large crowd. When Costentenus partnered with Barnum, he began to earn more than $1,000 a week. His wealth became so staggering that the New York Times wrote, "He wears very handsome diamond rings and other jewelry, valued altogether at about $3,000 [$94,699 in 2024 dollars] and usually goes armed to protect himself from persons who might attempt to rob him." Though Costentenus was fortunate, other freaks were not. Upon his death in 1891, he donated about half of his life earnings to other freaks who did not make as much money as he did.

One of Barnum's most famous hoaxes was early in his career. He hired a blind and paralyzed former slave named Joice Heth for $1,000. He claimed that this woman was 161 years old, but she was actually only 80 (with the oldest verified person in the world as of May 2025 being Jeanne Calment who was 122 years, 164 days when she died) This lie helped Barnum make a weekly profit of nearly $1,000. This hoax was one of the first, but one of the more convincing.

Barnum retired in 1865 when his museum burnt to the ground. Though Barnum was and still is criticized for exploitation, he paid the performers fairly handsome sums of money. Some of the acts made the equivalent of what some sports stars make today.

Tom Norman Barnum's English counterpart was Tom Norman, a renowned Victorian showman, whose traveling exhibitions featured Eliza Jenkins, the "Skeleton Woman", a "Balloon Headed Baby" and a woman who bit off the heads of live rats—the "most gruesome" act Norman claimed to have seen. Other acts included fleas, fat ladies, giants, dwarfs and retired white seamen, painted black and speaking in an invented language, billed "savage Zulus".Howell & Ford (1992), p. 69 He displayed a "family of midgets" which in reality was composed of two men and a borrowed baby.Howell & Ford (1992), p. 70 He operated a number of shops in London and Nottingham, and exhibited travelling shows throughout the country.