What's Under Your Feet in New York City? | Hacker News Reader

What's Under Your Feet in New York City?

practical.engineering

204 pointssohkamyung55 comments

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.

Might've been 2014? https://www.gettyimages.com/search/2/image?phrase=large+wate...

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.

And those weird booths that look like suicide booths, are no suicide booths. I love you, meatbags! Hello, it’s me, Bender Rodriguez!

I guess a robot would have to be crazy to be a folk singer...

Argelio

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.

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

This is actually rather impressive. Care to share the prompt you used?

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

https://en.wikipedia.org/wiki/New_York_City_synagogue_tunnel...

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

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.)

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.

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.)

It's God, he's talking about God.

“We’re Kosher, and have to answer to an even higher authority!”

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

That wasn't clear to me :-). But even still: the eruv is a rabbinical interpretation, not something attributed to God.

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".

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.)

> 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

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/

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/

Next up, they could build a low-earth-orbit eruv and call it a day

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.

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...)

I suspect the pork ban is twofold, preventing foodborne illness and also pigs can’t eat hay/grass like cows and goats, they eat what humans eat.

Sure. I also liked the idea that some of the rules are to promote tribalism by making clear defining lines.

A much weaker form compared to missions where people go out into the real world and get insulted and retreat back to the safety of their religion.

Jews have a very different relationship to religious laws than Christians. In his own time, Jesus was combating the predominant interpretation of the Jewish law in favor of his own interpretation, which is based more about the meaning and purpose of the law rather than the precise letter of the law. Sin isn't simply non-adherence to the law, it is an intrinsic part of human nature that needs to be redeemed, and all will fall short of the law. The important thing to remember in this is that in historically Christian cultures, we have inherited Jesus's view of the law that was directly and explicitly opposed to the version of Judaism that eventually became the default.

Jews think of the law differently. The law came directly from God- therefore, it is free from errors. If there are loopholes you can find in the law, God put them there for a reason and won't be mad if you use them. Some people even think that God put the loopholes in there as a reward for careful study of the law. Jews also don't think that there is eternal damnation in Hell facing anyone who defies the law, so I suppose the stakes are lower than for Christians so they can afford to be stricter.

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

Here's a video in which a Rabbi who is a member of the sect clarifies the story:

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

This is a clip from a comedy podcast called 9/11 is Gay.

> 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.

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.

> 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.)

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?

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...

> 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.

According to his LinkedIn profile:

> Over the past twenty-five years, Judge Perlmutter also has played a central role in the restoration and revitalization of Brooklyn's oldest synagogue building.

https://www.linkedin.com/in/adam-perlmutter-64799018a

> Prior to ascending to the Supreme Court bench, Perlmutter devoted significant amounts of time to gaining a Torah perspective on legal matters, studying the Talmudic tractate of Sanhedrin and Makos with Brooklyn activist Ari Noe for a year. Perlmutter had his hand placed on an ArtScroll Chumash when he was sworn in to his newest position by New York State Chief Judge Rowan Wilson.

https://vinnews.com/2025/02/19/jewish-justice-sworn-in-at-br...

Any mention of NYC underground is an opportunity for the antisemites to come crawling out of the woodwork.

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).

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.

You might run into "security thru obscurity".

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)

So many Ghostbusters II flashbacks watching this.

There was viral video in January 2024 showing what is under your feet in NY

Still waiting for someone to resurrect that old pneumatic tube system...

The Boring Company is on it lol

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.

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

Fascinating. Anything that grows up above ground has a proportionate growth below ground as well.

Pieces of Belgian cities?

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...

Nothing in that article suggests that the actual stones come from Europe. It seems like it would be rather impractical to import that much heavy material.

This report [0] from the Historic Districts Council in NYC says:

> Despite the name Belgian block, it remains unclear to what extent, and during what era, paving stones imported from Belgium may have provided the raw materials for New York City’s streets.¹ It is known that the city’s early paving stones included a type of six- inch-square traprock commonly called “Belgian” block, and said to have first been used in Belgium.

>1. While it has often been reported that Belgian blocks were imported to New York as ship ballast, we have not found primary evidence to confirm this practice.

https://hdc.org/wp-content/uploads/2017/08/HDC_Historic-Stre...

Interesting that there’s no primary evidence.

But your point about importing heavy material is mislaid: the blocks are intentionally heavy, because they (apocryphally) served as ballast.

Reply on news.ycombinator.com