Referred to as "monoliths", these sheet metal structures began to be constructed in the wake of the discovery of the Utah monolith, a 3 m (9.8 ft)-tall pillar made of metal sheets riveted into a triangular prism, placed in a red sandstone slot canyon in northern San Juan County, Utah.

The structure was placed there sometime between July and October 2016 based on images from Google Earth, but only attracted media attention after it was reported in late November 2020 by state biologists who discovered it during a helicopter survey of wild bighorn sheep.

This connection gave rise to speculation about an extraterrestrial origin, although the phenomenon has also been viewed as a craze or an Internet hoax,[6][7] with a number of features in common with crop circles.

[11] On December 14, 2020, a monolith appeared on top of a valley in Niknam-Deh, a small village approximately 15 kilometers east of Tehran.

[21] On December 29, 2020, another monolith was discovered in Maaseik in the province of Limburg, Unique to this appearance is that it also has a Latin saying: 'Fortis in unum' which means 'as one we are strong'.

[22] On December 12, 2020 a monolith was discovered between town Otrokovice and village called Tečovice in the district of Zlín In the middle of a field.

Similar to the other monoliths in shape and size, this one was found standing in the middle of a protected field in the small town of Virrat.

On December 8, investigators identified the people behind the installation, a group of artists from Castelli Romani in the Metropolitan City of Rome.

Its makers sent a note to local journalists claiming it was built by the X-Files character Fox Moulder [sic].

[56] On December 16, 2020, late in the evening, two men in black with a van were sighted digging a monolith in the center of a roundabout in Kampen.

[58] On December 9, 2020, a steel monolith was discovered at Kadzielnia nature reserve in Kielce and has since been fenced off with tape due to a possible increase of radiation in the area.

[61] On December 14, 2020, the satirical magazine ASZdziennik claimed to have constructed and placed the Warsaw monolith as a symbolic farewell to the year 2020.

[62] On November 26, 2020, a monolith was discovered in Romania on Bâtca Doamnei Hill in the city of Piatra Neamț, near the historical Petrodava Dacian Fortress.

[64] Jurnal FM stated on November 27 that they had actually "received a mail containing a clip and some photos regarding a strange structure found on a hill", on the preceding Tuesday, notably prior to the disappearance of the Utah monolith.

[65] The clip points out the structure's similarity to the Utah monolith, while also highlighting major differences in its reflective properties and texture.

In the morning the place where the monolith stood erect was empty, only a faint imprint remains on the ground covered by snow.

[88] On December 11, 2020, three monoliths were spotted: in Croydon, southern Greater London,[89] at a primary school in St Albans, Hertfordshire,[90] and in Lerwick, Shetland.

The Hertfordshire monolith disappeared again after one day, and was part of a writing experiment for the pupils according to Kevin Byrne, the premises manager of the school, in a phonecall with a Dutch investigator on December 21.

The monolith was made by Brent Siermachesky, the general manager at Alberta Custom Metal Fabricators, who said "this is just a little something to make people chuckle when they drive by and say, 'Hey look, we got one of those in Edmonton now too.

[109] On December 13, 2020, a 3 meter tall monolith was discovered by a local resident who was driving around the farmland in Eureka Springs, in which it was located.

Although of unknown origin, the monolith has undergone much speculation, as the land it currently resides on hosts an annual alien-themed music festival.

[111][112][113] On December 4, three young men from Orange County, referring to themselves as military veterans, livestreamed themselves destroying the monolith on DLive, replacing it with a large wooden cross and chanting "Christ is king!".

[116] According to the local mayor, Heather Moreno, "We are upset that these young men felt the need to drive five hours to come into our community and vandalize the monolith ...

The 2 meter tall triangular structure made of sheet metal was removed by local government officials the following day.

The 3 meter tall triangular structure consists of thick stainless steel panels that are 40 cm wide.

[140] The Las Vegas Metropolitan Police Department removed the object "due to public safety and environmental concerns" a few days after it was discovered.

Later that day at 17:00, one of the public cameras showed one or several people in a white van which led to a local business called the Blashfield Sign company.

The mystery of its appearance was short-lived, however, as it was quickly revealed to be a stunt organized through local country music radio station KSCS with the help of high school students from nearby Millsap, Texas.

This monolith did not remain mysterious for long, as it was claimed by a local steel manufacturer, Mountain Stainless Inc., as a marketing gimmick.

One major difference was that the monolith had a button on the east facing side that when pressed, would expose a container which had a metal piece with the eye of Ra, the Egyptian sun god.