What's Under Your Feet in New York City?

https://practical.engineering/blog/2026/7/21/whats-under-your-feet-in-new-york-city

Comments

evrydayhustlingJul 26, 2026, 9:36 PM
Around 2012 I was working near 5th Ave and 14th st, and there was a giant water main break. They had to dig about three stories down in a large intersection, and you could walk near the edge and look in.

It was extraordinary, like something out of a sci-fi where an alien ship has been torn open and the mess of pipes and wires looks organic. It was also a funny case of lost tech / organizational memory -- I heard they had to ask the union to help find retired folks who had worked on the lower levels and could explain why pipes were laid out the way they were.

mike_hockJul 26, 2026, 3:47 PM
That's where the mutants live. Also, there's a thousand year old, old New York City buried underneath that had bathroom booths with phones in them.
hinkleyJul 26, 2026, 9:23 PM
Don't touch the weird pink goo you find down there either.

And if your name is Winston, it's just best if you stay above ground, or stick to the subway system.

throw1234567891Jul 26, 2026, 6:57 PM
And those weird booths that look like suicide booths, are no suicide booths. I love you, meatbags! Hello, it’s me, Bender Rodriguez!
hinkleyJul 26, 2026, 9:20 PM
I guess a robot would have to be crazy to be a folk singer...
argelio4321Jul 26, 2026, 7:07 PM
Argelio
dbuxtonJul 26, 2026, 7:43 PM
I can’t read something like this without thinking of the late great Richard Scarry

Luckily ChatGPt does a pretty good impression https://chatgpt.com/s/m_6a6662e9af6c81918523fb06d1384e74

jayrotJul 27, 2026, 2:33 AM
This is actually rather impressive. Care to share the prompt you used?
dbuxtonJul 27, 2026, 10:25 AM
https://chatgpt.com/share/6a673180-0a78-83ed-abd0-d797c4d95a...

tldr the initial effort didn't seem to read the linked article so I copied and pasted the full text in

dataviz1000Jul 26, 2026, 3:09 PM
Meanwhile in place of power, cable, and phone lines there is a related 18 mile translucent line hung in order to turn the entire city into one big happy home called a *eruv* -- following the law of the highest of high courts to the letter. [0]

[0] https://www.youtube.com/watch?v=hSldb9IMDVU

woodruffwJul 26, 2026, 3:56 PM
AFAIK the eruvim are not dictated by “high courts” (there is no “high court” at all), but are instead constructed and maintained by various Orthodox groups. Not all Orthodox groups agree about their propriety either, so the presence of an eruv doesn’t necessarily mean that it’s recognized.

(Also pedantic, but it’s not the entire city: there’s a Manhattan eruv that covers a large part of Manhattan, while Brooklyn, Queens, and the Bronx have separate smaller eruvim.)

skissaneJul 27, 2026, 6:04 AM
> Not all Orthodox groups agree about their propriety either, so the presence of an eruv doesn’t necessarily mean that it’s recognized.

There have been some big fights about the topic: https://traditiononline.org/unpacking-the-iggerot/

Although from what I understand, Moshe Feinstein wasn’t opposed to eruvim in principle, he just viewed them as an inappropriate for a city like NYC

randallsquaredJul 26, 2026, 6:11 PM
There's a lot one could say about

> following the law of the highest of high courts to the letter.

but I don't think that "there is no 'high court' at all" is one, for believers.

woodruffwJul 26, 2026, 6:23 PM
You can look it up if you don’t believe me. Orthodox Judaism doesn’t have a supreme religious authority; it’s a general classification for ~hundreds of distinct sects and movements.

(Each movement has its own beis din, but there is not “high court” that unifies religious rulings across them. Which is why an eruv created by one group is often considered invalid by others.)

bombcarJul 27, 2026, 3:57 AM
It's God, he's talking about God.
woodruffwJul 27, 2026, 4:35 AM
That wasn't clear to me :-). But even still: the eruv is a rabbinical interpretation, not something attributed to God.
bombcarJul 27, 2026, 5:23 AM
The whole joke is that the Jews will even take God to court (where God is the Judge, Jury, and Defendant), and win - I believe there's a whatever it is they have about this: God basically ends up saying "Ha, I like the cut of your jib".
woodruffwJul 27, 2026, 10:19 AM
You’re probably referring to the Oven of Akhnai:

https://voices.sefaria.org/sheets/144163?lang=bi

(Talmudic interpretation doesn’t stress this story because it shows how much Jews love to argue, or because they can win arguments against God. It stresses the story because it demonstrates that the law has been received (“It is not in heaven”) and thus does not need to appeal to God. This, inter alia, is why nobody asks God for their opinion on eruvim.)

ButlerianJihadJul 27, 2026, 3:59 AM
“We’re Kosher, and have to answer to an even higher authority!”

https://youtu.be/lR1eeV5-M4U?is=anSmLPurh2pegvky

radicalityJul 26, 2026, 7:15 PM
I live in nyc, when I first heard of the eruv couldn’t believe they would come up with such elaborate hacks just to ‘technically’ still be following their religious laws! Now if I remember I try and spot it when out.

It also has a status page! https://eruv.nyc/

frantathefrantaJul 26, 2026, 8:43 PM
Somebody posted on HN before about an eruv index, that’s how I found my city had one as well[0]. I assume they got sort of popular around Jewish neighborhoods.

[0]https://eruv-columbus.com/

radicalityJul 26, 2026, 10:46 PM
Next up, they could build a low-earth-orbit eruv and call it a day
lesuoracJul 26, 2026, 9:25 PM
Idk it makes sense to me.

Like a lot of the rules are very fuzzy in their origin. The whole kosher business comes from a passage about "Not boiling a kid in it's mothers milk". I think most people would interpret that much more literally and you couldn't kill a child goat (kid) and boil it in it's mothers milk; and probably also extend it to other animals like cows. But I'd still think that killing a kid and putting a slice on cheese on the meat would be fine.

So if somebody is going to be obtuse with what you can do it seems like it'd be good fun to figure out all the ways around it.

to11mtmJul 26, 2026, 11:47 PM
I think most of the kosher rules come from a sort of 'this is the most practical rule we can make at the time to keep people safe' sort of thing.

Stuff like disease (i.e. most of the other rules about kosher animal prep including 'inspection',) allergies (shellfish ban), heck even pasteurization (going back to the 'boiling in milk', what are the odds that the milk hit the right temperature all throughout versus only some of it boiling, which in fact could encourage certain bad bacteria to grow, let alone whatever's in the likely uncooked meat being able to feed off the whole thing...)

cogman10Jul 26, 2026, 3:31 PM
This is a very weird story.

Religious infighting with 2 fundamentalist sects that somehow boiled down to some people digging a tunnel connecting 2 buildings because of... reasons? Like it seems like they thought that if they built the tunnel that'd magically lead to everyone deciding "You know what, this expansion project is a good thing!"

Very bizarre.

Regardless, I'm glad it got shut down before a collapse killed someone.

woodruffwJul 26, 2026, 3:38 PM
> Religious infighting with 2 fundamentalist sects that somehow boiled down to some people digging a tunnel connecting 2 buildings because of... reasons?

The very short version is that both groups claim ownership of that building, and one of them wants to expand it significantly. Neither group is allowed to modify the building because of a court order, so the one that wants to modify it did it surreptitiously in an attempt to create facts on the ground that would modify the status quo.

(Obviously none of this is sensible, but the actual reasons are pretty quotidian.)

masfuerteJul 26, 2026, 4:00 PM
It's quite frustrating. The story ends with:

> four defendants refused to accept a plea deal and were set to be tried in April 2025

I can find loads of stories reporting those facts, but I can't find an account of what happened next. Did they change their pleas? Were they tried?

BrybryJul 27, 2026, 8:34 AM
Looks like the cases are still ongoing.

You can find the defendant names in this article (from the wikipedia link) [1] and then look up some basic case info by name: google "new york WebCriminal Defendant Search" and then search by defendant name + Kings Supreme Criminal Court. You'll see information like case number and next court date. You can also find similar info with "nyscef case search".

When I was clicking around, the website sometimes had language about not linking to it directly without permission so that's why no link... even though it seems a bit silly.

[1] https://www.nbcnewyork.com/brooklyn/men-charged-brooklyn-syn...

ButlerianJihadJul 27, 2026, 9:23 AM
> Huebner downplayed the seriousness of the charges and said the defendants are all Israelis studying to be rabbis ... Two of the men have dual U.S.-Israeli citizenship and none are married.

> The 13 people, all young men, pleaded not guilty in State Supreme Court in Brooklyn ... Another four defendants were absent because they were in Israel, according to their lawyer, Levi Huebner.

> Justice Adam Perlmutter ordered the defendants ... to turn over their passports.

rdtscJul 26, 2026, 3:12 PM
An illegal tunnel in a densely populated city like that is a bold move.

This was unexpected though:

> stills taken from videos of the synagogue's interior as well as the room leading to the tunnel, which showed a stained mattress and high chair, respectively, fueled antisemitic conspiracy theories

> A USA Today fact-check stated that the stained mattress seen in viral videos had been removed from behind wood paneling of the synagogue rather than from the tunnel itself, undermining online speculation that the mattresses were in the tunnel

noworriesnateJul 26, 2026, 6:42 PM
Here's a video in which a Rabbi who is a member of the sect clarifies the story:

https://xcancel.com/Truthtellerftm/status/197901264211193488...

burkamanJul 26, 2026, 7:30 PM
This is a clip from a comedy podcast called 9/11 is Gay.
mschuster91Jul 26, 2026, 8:52 PM
> An illegal tunnel in a densely populated city like that is a bold move.

I'd say it was an utterly braindead move and pretty much everyone involved is lucky to be alive.

There's just so, so much dangerous stuff you can hit below ground - high voltage cables that really, really do not like it if you even nick them, high current cables giving off nasty electromagnetic fields, ordinary low voltage cables whose isolation is already degraded, old water, gas, steam and sewer mains that may or may not burst simply because the only thing holding together the rust is the pressure from the soil, other, maybe long forgotten tunnels...

And that's before even getting into the issue of potentially getting caved in, creating a sinkhole or an ingress avenue for stormwater.

programmertoteJul 26, 2026, 6:10 PM
One of the most informative videos from Practical Engineering channel. I thought I knew NYC infra fairly well, but I learned so much from that video still (like how NYC's electric grid is actually a grid and more fault tolerant).
radicalityJul 26, 2026, 7:21 PM
This is quite informative and useful as I live in NYC. I think in the video he mentioned that the city is collecting all that data on what’s underground to collect all in a database and make repairs easier - anyone know if such data is or will be public, like on data.ny.gov ? And what I’m getting at, is it would be really cool to have this kind of 3d visualization like in the video, but based on actual real data so I could view what’s actually underneath the streets I walk every day.
jayrotJul 26, 2026, 11:44 PM
Don’t know about this specifically but if you ever watch Rainbolt you know that NYC is pretty legendary for providing crazy data to the public (for example a database of all trees, or insane detail street information)
euroderfJul 26, 2026, 9:20 PM
You might run into "security thru obscurity".
willworktill4pmJul 27, 2026, 7:33 AM
There was viral video in January 2024 showing what is under your feet in NY
xg15Jul 26, 2026, 9:43 PM
Still waiting for someone to resurrect that old pneumatic tube system...
markdownJul 27, 2026, 7:53 AM
The Boring Company is on it lol
theletterfJul 26, 2026, 7:26 PM
This is fantastic, but I so hoped it would come with an infographic of NY's underworld, slice of cake style. I recall seeing one somewhere, but my attempts at finding it again all failed.
ozyschmozyJul 26, 2026, 8:31 PM
The video does have something like that, it's not labeled though, rather he goes through each part and highlights the part he's talking about
hinkleyJul 26, 2026, 9:24 PM
So many Ghostbusters II flashbacks watching this.
zkmonJul 26, 2026, 4:31 PM
Fascinating. Anything that grows up above ground has a proportionate growth below ground as well.
barrenkoJul 26, 2026, 7:29 PM
Pieces of Belgian cities?
woodruffwJul 26, 2026, 7:42 PM
If you're referring to the Belgian blocks[1], I don't think they're actually from Belgium specifically, just Europe in general. Although some might be from Belgium!

[1]: https://sohobroadway.org/soho-broadway-block-by-belgian-bloc...

VoodooJuJuJul 26, 2026, 2:27 PM
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dfaoidsoiJul 26, 2026, 3:31 PM
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