A circus is a company of performers who put on diverse entertainment shows that may include clowns, acrobats, trained animals, trapeze acts, musicians, dancers, hoopers, tightrope walkers, jugglers, magicians, ventriloquists, and unicyclists as well as other object manipulation and stunt-oriented artists.

[1][2][3] In 1768, Astley, a skilled equestrian, began performing exhibitions of trick horse riding in an open field called Ha'penny Hatch on the south side of the Thames River, England.

"[6] In the book De Spectaculis, early Christian writer Tertullian claimed that the first circus games were staged by the goddess Circe in honor of her father Helios, the Sun God.

In Ancient Rome, the circus was a roofless arena[8]: 2  for the exhibition of horse and chariot races, equestrian shows, staged battles, gladiatorial combat, and displays of (and fights with) trained animals.

After being rebuilt several times, the final version of the Circus Maximus could seat 250,000 people; it was built of stone and measured 400m in length and 90m in width.

[18] Astley was followed by Andrew Ducrow, whose feats of horsemanship had much to do with establishing the traditions of the circus, which were perpetuated by Hengler's and Sanger's celebrated shows in a later generation.

In arenas too large for speech to be easily audible, the traditional comic dialogue of the clown assumed a less prominent place than formerly, while the vastly increased wealth of stage properties relegated to the background the old-fashioned equestrian feats, which were replaced by more ambitious acrobatic performances, and by exhibitions of skill, strength, and daring, requiring the employment of immense numbers of performers, and often of complicated and expensive machinery.

Nonetheless, a good number of travelling circuses are still active in various parts of the world, ranging from small family enterprises to three-ring extravaganzas.

In 1919, Lenin, head of Soviet Russia, expressed a wish for the circus to become "the people's art-form", with facilities and status on par with theatre, opera and ballet.

This includes a strong trend for developing new apparatus and movement languages based on the capacities, experience and interests of individual performers, rather than finding new ways to present traditional repertoire.

The physical and creative skills that circus artist/es perform are known as disciplines, and are often grouped for training purposes into the broad categories of juggling, equilibristics, acrobatics, aerial and clowning.

These disciplines can be honed into individual acts, which can be performed independently and marketed to many different prospective circus employers, and also used for devising solo or collaborative work created specifically for a single project.

Famous circus clowns have included Austin Miles, the Fratellini Family, Rusty Russell, Emmett Kelly, Grock, and Bill Irwin.

The title clown refers to the role functions and performance skills, not simply to the image of red nose and exaggerated facepaint that was popularised through 20th Century mass media.

While the types of animals used vary from circus to circus, big cats (namely lions, tigers, and leopards), foxes, wolves, polecats, minks, weasels, camels, llamas, elephants, zebras, horses, donkeys, birds (like parrots and doves), sea lions, bears, monkeys, and domestic animals such as cats and dogs are the most common.

Going as far back as the early eighteenth century, exotic animals were transported to North America for display, and menageries were a popular form of entertainment.

Van Amburgh entered a cage with several big cats in 1833, and is generally considered to be the first wild animal trainer in American circus history.

[53] On behalf of the Ministry of Agriculture, Nature and Food Quality of the Netherlands, Wageningen University conducted an investigation into the welfare of circus animals in 2008.

[56] In its January 2010 verdict on the case, brought against Feld Entertainment International by the American Society for the Prevention of Cruelty to Animals et al., the Court ruled that evidence against the circus company was "not credible with regard to the allegations".

[57] In lieu of a USDA hearing, Feld Entertainment Inc. (parent of Ringling Bros.) agreed to pay an unprecedented $270,000 fine for violations of the Animal Welfare Act that allegedly occurred between June 2007 and August 2011.

[63] In 1998 in the United Kingdom, a parliamentary working group chaired by MP Roger Gale studied living conditions and treatment of animals in UK circuses.

Gale told the BBC, "It's undignified and the conditions under which they are kept are woefully inadequate—the cages are too small, the environments they live in are not suitable and many of us believe the time has come for that practice to end."

"; however, in 2007, a different working group under the UK Department for Environment, Food and Rural Affairs, having reviewed information from experts representing both the circus industry and animal welfare, found an absence of "scientific evidence sufficient to demonstrate that travelling circuses are not compatible with meeting the welfare needs of any type of non-domesticated animal presently being used in the United Kingdom.

[66] The Animal Defenders International non-profit group dubbed this "a huge embarrassment for Britain that 30 other nations have taken action before us on this simple and popular measure".

[69] A bill to ban the use of wild animals in travelling circuses in Wales was introduced in June 2019, and subsequently passed by the Welsh Parliament on 15 July 2020.

There are nationwide bans on using some if not all animals in circuses in Austria, Belgium, Bolivia, Bosnia and Herzegovina, Bulgaria, Colombia, Costa Rica, Croatia, Cyprus, Czech Republic, Denmark, Ecuador, El Salvador, Estonia, Finland, Greece, Hungary, India, Iran, Ireland, Israel, Italy, Malta, Mexico, the Netherlands, Norway, Panama, Paraguay, Peru, Poland, Portugal, Singapore, Slovenia, Sweden, Switzerland, and Turkey.

Mera Naam Joker (1970), a Hindi drama film directed by Raj Kapoor which was about a clown who must make his audience laugh at the cost of his own sorrows.

Notable examples of circus-based fiction include Circus Humberto by Eduard Bass, Cirque du Freak by Darren Shan, and Spangle by Gary Jennings.

The novel Water for Elephants by Sara Gruen tells the fictional tale of a circus veterinarian and was made into a movie with the same title, starring Robert Pattinson and Reese Witherspoon.

A circus-based television series called Circus was also telecast in India in 1989 on DD National, starring Shahrukh Khan as the lead actor.