Item #: SCP-XXXX

Object Class: Safe

Special Containment Procedures: Area 837B has been constructed around SCP-XXXX under the pretense of establishing a protective habitat for a previously unknown and critically endangered species of inland Aptenodytes. The four-square-kilometer facility includes temporary facilities to support the exploration of SCP-XXXX and is surrounded by a continuously patrolled perimeter fence. The entrance to SCP-XXXX is enclosed in a 50 m opaque geodesic dome. Due to the geographical remoteness of SCP-XXXX, no additional containment procedures are deemed necessary at this time.

Description: SCP-XXXX is an underground structure of unusual size located beneath the Antarctic Plateau. It consists of two sub-structures, designated SCP-XXXX-1 and SCP-XXXX-2.

SCP-XXXX-1 is a 2.4 m × 3.6 m × 280.45 km tunnel that intersects the surface of the plateau at 87°██′██″ S., −126°██′██″ W. It descends at an angle of 2.55° (measured 5 m from the opening) to a depth of approximately 6.3 km beneath the surface. At its terminus, SCP-XXXX-1 opens into an immense chamber designated SCP-XXXX-2. Estimates based on dead reckoning place SCP-XXXX-2 within ten kilometers of the geographic south pole.

Both SCP-XXXX-1 and SCP-XXXX-2 are constructed out of cubic blocks of basalt measuring 1.2 m and weighing approximately 5.2 tonnes each. The origin of these blocks is unknown. Radiometric dating has thus far been unsuccessful due to abnormally low concentrations of potassium, rubidium and uranium isotopes in the stone. The best-confidence upper limit for the age of the blocks is 9.9 Gy, which is somewhat in excess of twice the currently estimated age of the Earth.

SCP-XXXX-3 is the designation for the phenomenon located at the approximate center of SCP-XXXX-2. SCP-XXXX-3 appears to be an ovoid-toroidal volume of circulating hot gas 21 m in diameter at its widest point and 27 m long, oriented with its axis of symmetry parallel to SCP-XXXX-1. The lowest point of SCP-XXXX-3 is approximately 5 m above the floor of SCP-XXXX-2. SCP-XXXX-3 emits light in a spectrum close to that of a blackbody with a temperature of 5900K. However, the luminance of SCP-XXXX-3 is inconsistent with its apparent composition and temperature, and it appears to radiate no heat into its environment. No abnormal radiation or magnetic fields have been detected in proximity to SCP-XXXX-3.

Document XXXX.1: Discovery

SCP-XXXX was initially discovered on ██/██/████ during a routine review of Earth-observation imaging. The feature was initially believed to be a moulin1 of unknown origin in the East Antarctic Ice Sheet. Foundation satellite KNOTHOLE-33 was tasked to obtain high-resolution imagery of the feature. It was at this time that the geometric properties of the feature were identified. A Foundation research team was redirected from [DATA EXPUNGED] confirmed the apparently anomalous nature of the structure. In ██/████ Area 837B was constructed to contain SCP-XXXX and to facilitate exploration of the structure.

Document XXXX.2: Exploration Reports

Document XXXX.3: Incident Reports

Addendum XXXX.1: Subsequent to Incident-XXXX-01, SCP-XXXX-3 is provisionally classified as a Grade 2 cognitohazard. Human exploration of SCP-XXXX is suspended indefinitely. Robotic exploration requires Level 4 authorization. Request for upgrade to class Euclid is under review.

Addendum XXXX.2: Request for upgrade to class Euclid is denied.

Addendum XXXX.3: Request to seal entrance to SCP-XXXX is under review.

Addendum XXXX.4: Request to seal entrance to SCP-XXXX is denied.