Item #: SCP-581-FR
Threat Level: Orange ●
Object Class: Safe
Special Containment Procedures: The sewer grate initially covering access to SCP-581-FR has been removed and is now kept in a secure Foundation area. A new regular grate has been installed and welded to the ground. It is forbidden to get exposed to natural light inside SCP-581-FR.
All access to SCP-581-FR is forbidden until further notice.
Description: SCP-581-FR is the designation for a vertical shaft looking like a sewer entrance located near the city of Charleroi, Belgium, as well as the structure under the hole. It was covered by a cast iron circular grate looking like the other grates in the city until the cover was removed. The outside face of this cover displays "Services de Charleroi - Pourdière" while the inside face shows "SCP Foundation Department of Abnormalities".

One of the SCP-581-FR corridors. Notice the lock holes on the doors, also inverted.
The shaft is equipped with a steel ladder going down about 96 metres before reaching the ceiling of an artificial cavity. It is thus necessary to jump in order to complete the last metres.
The cavity located under the shaft is an infrastructure akin to a non-anomalous factory seemingly derelict. The main anomaly of SCP-581-FR lies in its inverted architecture and geometry: The ceiling looks like the floor, and the floor looks like the ceiling; door frames start centimetres above the floor, and end at the ceiling. A significant amount of debris, and sediment can be seen on the ceiling. No object brought into SCP-581 during its explorations has been affected by this anomaly.
SCP-581-FR is arranged like a complex of factories and university from the late 1970s that would have been abandoned and/or pillaged over a time span of 50 years. The structure has mostly empty rooms, break rooms, airlocks that would indicate that there was industrial petrochemical activity inside of the factory, but it also has dormitories, classrooms, toilets, communal showers, and even the remains of a mini-market. None of the brands on the few remaining items in the mini-market are known.

A SCP-581-FR-1 instance. Light seem to come from below the instance.
Some rooms of SCP-581-FR are fully covered with an assembly of steel plates, pipes and a diverse array of mechanical pieces extending almost to the ground whose origins and operating principles are unknown. This assembly is henceforth designated SCP-518-FR-1. It is to note that during the first exploration of SCP-581-FR by Theta-90 ("Angle Grinders"), one of the SCP-581-FR-1 instance did contain a piece of torn paper that seemed to once display the Foundation logo as well as a number ending in 14. The nature of this document is unknown. None of the SCP-581-FR-1 instances seem mobile nor equipped with a mechanism to potentially activate it. The dilapidated condition of some mechanical pieces or pipes found in SCP-581-FR equipment seem to indicate they are far older than the rest of the facility.
Unexplicably, some light sources such as the neon tubes on the ground are still active, even if clearly suffering from under-voltage. The source of the electrical current powering those sources is unknown. Light coming from outside the facility is also visible, as if light from the Sun was hitting some windows with an upward angle despite the relevant depth of SCP-581-FR. It is to note that those windows are systematically covered from the outside using white paint to block the view from either side. The high amounts of dust that are visible thanks to these luminous rays invariably fall towards the ceiling, and not towards the floor.

An example of this light source. The holes circled with barriers on the roof haven't been observed yet.