Tsarichina is a small village in Sofia Province in western Bulgaria, northwest of Sofia. In late 1990, during the country's difficult transition away from communist rule, the Bulgarian military began a highly unusual excavation there. The project later became widely known by names translated as “Sunray” or “Lightbeam” and developed into one of Bulgaria's most enduring modern mystery stories. The excavation itself is not merely folklore: Bulgarian media and later participants confirm that the General Staff of the Bulgarian Army authorized and conducted an operation at Tsarichina.

Work began on 1990-12-06. Bulgarian retrospective reporting describes military vehicles and excavation equipment arriving at the village and beginning work under military authority. One early explanation involved a supposed treasure associated with medieval ruler Tsar Samuil, although accounts differ concerning precisely how the proposal originated and which individuals first persuaded senior officers to investigate it. The diversity of later versions makes it important not to present one detailed origin story as established unless it can be tied to surviving contemporary military documentation.

Psychics and individuals claiming extrasensory abilities soon became central to the operation. Among the best-known participants was Elisaveta Loginova, who decades later continued to discuss involvement in the project publicly and was interviewed about Tsarichina by Bulgarian National Television. Participants described receiving information through psychic, telepathic, or otherwise extraordinary means, and the supposed objective of the excavation appears to have changed as the project developed.

Later accounts therefore offer strikingly different descriptions of what the excavation was intended to uncover. These include Tsar Samuil's treasure, ancient archaeological material, previously unknown knowledge about human origins, a prehistoric or proto-human being, and a non-human or extraterrestrial entity. One particularly famous version describes a hermaphroditic or sexless humanoid connected with humanity's origins. These are documented as claims made about the operation, not as discoveries established by the excavation.

The physical work itself was substantial. Widely cited accounts describe the military excavating an underground passage approximately 160 to 165 meters long and reaching a vertical difference or depth of roughly 70 meters. Whatever the validity of the paranormal reasoning surrounding the project, the excavation therefore represented a genuine expenditure of military personnel, equipment, time, and state resources rather than a purely fictional legend invented after the fact.

Stories about unusual occurrences accumulated during and after the project. Participants and later retellings described mysterious lights, unidentified aerial objects, equipment problems, unusual physical sensations, strange underground formations, psychic communications, and other anomalous events. Bulgarian-language reporting continues to repeat claims of unusual violet lights around the former excavation site. However, establishing which of these reports were recorded contemporaneously during the operation and which developed or expanded through later interviews and paranormal retellings remains difficult.

Claims that the excavators discovered ancient artificial tunnels, inscriptions, force fields, alien artifacts, or the remains of an unknown humanoid are especially poorly established publicly. No independently verifiable archaeological assemblage, biological specimen, published scientific analysis, or documented artifact from the excavation has established such a discovery. Accounts asserting that something extraordinary was found should therefore be treated as claims surrounding the operation rather than as demonstrated results.

The project ended on 1992-11-19. Modern summaries commonly report that the excavation was abandoned because of expense or lack of useful results and that the entrance was subsequently sealed with concrete. The sealed site subsequently became an important physical element of the legend, encouraging suspicions that authorities had concealed something significant rather than simply terminating an unsuccessful and increasingly difficult project.

Questions surrounding the project's documentation have helped those suspicions persist. In 2025, Bulgarian National Television reported that the location of documentation produced during the project remained unclear and described continuing uncertainty over who possessed the records. The absence or uncertain disposition of records is historically interesting, but it does not by itself demonstrate that documents were destroyed or removed in order to conceal an extraordinary discovery.

The later mythology surrounding Tsarichina grew considerably beyond the facts that can presently be established. The site has been called “Bulgaria's Area 51,” and stories now incorporate extraterrestrial contact, hidden knowledge about human evolution, predictions attributed to famous mystic Baba Vanga, mysterious deaths, missing documentation, unidentified aerial phenomena, and secret discoveries suppressed by authorities. Some elements may derive from genuine participant testimony, but the chronology and independence of many claims require further reconstruction before they can be treated as contemporary evidence.

The Tsarichina Hole is therefore most compelling because an extraordinary institutional event unquestionably occurred even though the extraordinary explanations remain unverified. A national military organization spent nearly two years excavating beneath a Bulgarian village while psychics and paranormal ideas played a documented role in the operation. What the military expected to find, why senior officials continued the project for so long, what observations were actually recorded during the excavation, and what became of the project's documentation remain legitimate historical questions. None of those uncertainties presently establishes an extraterrestrial discovery, but neither should the very real and highly unusual military excavation be reduced to folklore that never happened.