Per 
SCP-XXXX.
Special Containment Procedures: Tests involving SCP-XXXX are to be conducted with specially-tuned recording devices, with the purpose of picking up otherwise inaudible sounds through insonorized surfaces. Aldwych Station is to be condemned, with the current cover being renovations.
Following Addendum XXXX/3, tests with SCP-XXXX are to be halted.
Description: SCP-XXXX is a partly-soundproof 2 meter tall by 1.5 meter wide metal door located within the abandoned Aldwych underground station in London, England. When opened, SCP-XXXX leads to an extradimensional space1, consisting of a 3 meter long hallway, ending on another instance of SCP-XXXX, designated SCP-XXXX-2, subsequently leading to a tertiary instance, designated SCP-XXXX-3, and so on. As of writing, SCP-XXXX-A is believed to continue indefinitely.
When closed, sounds with sufficient volume trespassing SCP-XXXX will have an echo, with a volume as if it were spoken inside a larger room than expected, estimated at 503 meters. It is currently believed that, when SCP-XXXX is closed, its backside is connected to a different extradimensional space2 than when opened. Viewing SCP-XXXX-B has been impossible, as SCP-XXXX blocks all known methods of imaging.
Upon unknown circumstances, sounds can be heard coming from SCP-XXXX-B. It is currently believed that these are some form of response from SCP-XXXX.
SCP-XXXX was discovered on 4/7/2001, following reports of unknown voices speaking somewhere within the Aldwych station. Early blueprints for the construction of the London underground system show SCP-XXXX used as a bathroom. However, final construction plans do not show the platform in which SCP-XXXX is located, nor SCP-XXXX itself.
No reports of SCP-XXXX exist before the abandonment of the station in 1994.
Addendum XXXX/1 - Partial Test Log:
| Test Number | Date | Action Performed | Response |
|---|---|---|---|
| 3 | 4/7/2001 | Knocked once. | None. |
| 5 | 4/7/2001 | Knocked twice. | None. |
| 7 | 4/7/2001 | Knocked thrice. | Three knocks. |
| 13 | 5/7/2001 | Walked to to SCP-XXXX-5, then screamed at 110 dB. | Scratching. |
| 20 | 5/7/2001 | Walked to SCP-XXXX-17, then kicked the door. | A similar kicking sound. |
| 23 | 12/10/2001 | Walked to SCP-XXXX-53. | Construction sounds.3 |
| 25 | 15/10/2001 | A recording of a child stating "hello" is played on repeat. | An unidentified voice. Showed confusion, and stopped when the sound bite did. |
| 26 | 15/10/2001 | Walked to SCP-XXXX-61. | Strong footsteps, followed by several doors opening. Screamed once, then apparently broke down crying, and went silent. |
| 27 | 15/10/2001 | Opened SCP-XXXX, then closed it with greater force. | None. |
| 33 | 1/12/2001 | Walked to SCP-XXXX-22, then knocked continuously for 5 minutes. | An unidentified voice. Believed to be different from the one in Test 25. |
| 38 | 12/1/2002 | Walked to SCP-XXXX-21. | A male voice was heard screaming "Please open the door" repeatedly. An electrical noise followed, and the voice went silent. |
| 44 | 7/5/2002 | None. | A hushed, female voice. Believed to be narrating a life event. Acted startled before stopping. |
| 50 | 19/8/2002 | Walked to SCP-XXXX-35, then attempted to converse. | None. |
Addendum XXXX/2 - Interview with D-19215:
Foreword: D-19215, conductor of all tests from 13 onwards, returned from Test 50 requesting an interview regarding the nature of SCP-XXXX, which was granted.
Interviewee: D-19215
Interviewer: Researcher Luca
<BEGIN LOG>
Luca: Hello, D-19215. You requested an interview, correct?
D-19215: Yep.
Luca: So, what seems to be the issue, D-19215? We wouldn't have called you in for a report until tom-
(D-19215 interrupts.)
D-19215: You know how far down that door goes?
Luca: Well, yes. It's theoretically infinite.
D-19215: Don't give me that bullshit. None of your fancy-shmancy words. That's some unnatural stuff, right there. Fucking unnatural. And that's coming from a guy who's talked to who-knows-what, been sent to god-knows-what dimension because of you guys, and probably kissed Death, one time or another. That was fucking spooky.
Luca: Pardon me. It goes for a… 'very, very long time.'
D-19215: Yeah, sure. That door's had voices behind it, right. For a long, long time? Longer than I've been testing?
Luca: W-well, yes.
D-19215: And you've heard them do some… pretty normal people shit, right?
Luca: I'm not at liberty to discuss results other than your tests with you.
D-19215: So, yes.
Luca: I'd encourage you to calm yourself, D-192-
(D-19215 interrupts once more, this time standing up as he throws his chair to the floor. He pauses, before picking it up and gently pushing it back in.)
D-19215: Listen to me. Don't talk. You haven't been in there. You don't know what I've heard. You don't know what it's said, what they've said, what I've heard them say. I-It gets closer. I get closer to the voices. But you wouldn't fucking know that, because I'm the one doing the testing, and not you!
Luca: I can request you a psych eval, Milo, just calm down. Please. Before I have to call security.
D-19215: No. No no no, I'm not calming down. Do you understand what I heard? Just let me tell you, for fuck's sake. Shut up and let me do the talking for once, ok? (D-19215 pauses for a second, stopping Researcher Luca before he can respond.) That door. The test was a normal one, ok? Right.
Luca: And presumably, you noticed some abnormal results not at all associated with prior tests?
D-19215: Yes, I- (D-19215 sighs.) Yes, ok? I went through a buncha doors, like you guys had told me to, cause the doors were being… 'uncooperative.' So I go through a bunch, and I'm just fuckin' tired of knocking ok? Like, I'm fucking tired of it. Knocking gets boring.
Luca: Understandably.
D-19215: Yep. So I decide to just… do something I hadn't before. (He laughs.) I began to squeal. Just super-duper high pitched. Just me going "eeeeeeeee" for about a minute or two.
Luca: And this did what?
D-19215: Just before I tell you, Doc, I wanna ask. How… much like you do you think you are? How important?
Luca: I suppose… like me? The only me I can be?
D-19215: That's… That's what I thought too. I-I thought that too. But that was before.
(D-19215 remains silent for 24 seconds.)
Luca: Milo?
D-19215: … I thought my life mattered.
(D-19215 is silent for the remainder of the interview, and refuses to talk about SCP-XXXX. He is then taken to psychological evaluation. Two months later, D-19215 is reported dead, having presumably commited suicide during testing with SCP-███.)
<END LOG>
Addendum XXXX/3 - Audio Log:
Foreword: Researcher Luca was taken to SCP-XXXX-543 for testing, equipped with a recording device and provisions. Upon return, the following log was recovered.
<BEGIN LOG>
[0:00]: (Researcher Luca is instructed to turn on device.)
[1:23]: (Faint footsteps, gradually closing in.)
[2:33]: (Researcher Luca hears the footsteps, and opens SCP-XXXX-544, then proceeds to -545. The footsteps keep closing in.)
[2:45]: (Footsteps stop, and a knocking noise can be heard. Researcher Luca opens SCP-XXXX-546. A low, indiscernible voice can be heard.)
[2:56]: (Researcher Luca opens SCP-XXXX-547, then -548, 549, 550 and 551. The voice stops, then a different voice starts, much louder, although still indiscernible.)
[3:11]: (Researcher Luca opens SCP-XXXX-552, then -553, and -554. The voice does not seem any closer. Ten seconds later, it stops.)
[3:30]: (Researcher Luca knocks into SCP-XXXX-554, then screams.)
[3:35]: (The second voice shouts.) D-19215, record that! Before it stops!
[3:47]: (Researcher Luca opens SCP-XXXX-555, then -556, -557, -558, -559, -560, -561, and 562. The voices do not seem any closer. The first voice speaks again, apparently scared. Researcher Luca opens SCP-XXXX-563, -564, 565, 567, then 568. The voices then stop altogether.)
[4:43]: (Researcher Luca opens SCP-XXXX-569, -570, -571, then -572.)
[5:23]: (Researcher Luca cries.)
Note: Upon further examination, it was noted that the two unknown voices corresponded to D-19215 and Researcher Luca. Research pending.
