The world is full of hidden communities with people living out a private existence. Isolated from the world, they feel more at home in caves, sewers, and underground subways.

Some seek places underground to get away from the surface, while others happen upon them by chance. What they discover is a world covered in darkness that often gets the leftovers of the world above.

Dubbed “mole people,” there are all kinds of myths and tales that surround underground dwellers and the world they live in. Many even reside right under the public’s noses in major cities detailed below.

For more fascinating sights underneath the surface, see photos of secret tunnels we weren't supposed to see.

20 Their Eyes Acclimate To Darkness

It’s dark underground and, while there’s some electricity in parts, it’s not always lit. “It takes time for your eyes to adjust,” said Marc Singer, who lived under New York in the ‘90s (The Guardian).

It’s a testament to the human body that it’s able to adjust to imperfect conditions.

19 They Have To Fend Off Wild Animals

Part of living underground is staking one’s claim, even if it means guarding it against animals. In a piece highlighting underground dwellers, NY Post noted that residents had to repel a raccoon trying to infringe on their domain.

Contending with wild animals isn’t just for people with backyards, but those living underground too.

18 Thousands Live Under New York City

Jennifer Toth wrote a book called “The Mole People: Life in the Tunnels Beneath New York City.” While some have refuted parts of what the book asserts, she claims that thousands live below the City That Never Sleeps.

Finding shelter in the city’s subways and sewers, they’ve made use of abandoned areas few above dare to explore.

17 They Take Showers Under Pipes

There are fewer amenities living underground, but human needs don’t vanish overnight. In a piece by The Irish Times, a writer spotted people taking showers under pipes.

Without the freedom to control water flow or the cleanliness of what pours out of it, underground dwellers take what they can get.

16 Babies Are Born There

Many people live underground the same way they would on the surface. They cook food, watch TV and even give birth. The site Narratively reports that Jennifer Toth’s book, “The Mole People,” confirms babies were born underground.

Not only is the environment not suited for it, but there isn’t the kind of doctors and delivery tools that’s available in hospitals.

15 They Have Extensive Shoe Collections

Those that gravitate towards tunnels underground tend to be homeless. They don’t own a lot, which makes many of the items they find discarded valuable. One resident, who calls himself Travolta, accumulated thousands of shoes, according to NY Post.

The source also notes that shoes seem to be the most abundant piece of garbage found there.

14 They Rest For Several Days At A Time

Not everyone who lives underground lies down for several days in a row, but some have admitted to it. “I was so cold, didn’t get up for at least three days,” one resident shared with NY Post.

The constant darkness down below may also be a factor that causes people to lose track of time.

13 Graffiti Artists Paint The Walls Of Their Homes

The Riverside Park tunnel in New York wasn’t just known for its “mole people,” but graffiti artists too. Chris Pape was one of them. The site Untapped Cities notes that his murals and paintings surrounded a hundred people living there at one point.

The tunnel became active again in the ‘90s though, so everyone had to vacate the premises.

12 Railroad Corporations Give Them More Trouble Than Cops Do

Many take up residence in the subways and railroads underground. This can create a problem for those that offer train services, like Amtrak or city transit, whose personnel can encounter them in tunnels and tracks.

“Regular police ain’t bothering me,” shared one underground dweller with Narratively. “But Amtrak, they can be bad.”

11 They Have Trouble Going Back To The Surface

There’s a common challenge among underground dwellers: it’s hard to make it up above. Narratively told a story about Bob Kalinski, who tried to live in the public housing system but didn't feel as valued there. He went back underground.

Another one received an offer to make a movie based on his life, but he ended up coming back too.

10 They Don’t Eat Rats

Plenty of rumors spread about “mole people” living below the surface. One of them asserts that people living there eat rats to get by. When a writer with The Irish Times told this to a resident, they laughed.

Contrary to these widely disseminated ideas, however, The Irish Times reports they don’t, in fact, eat rats.

9 They Have To Navigate Tricky Passages

Underground tunnels weren’t built with long-term residents in mind. That makes many of their homes below ground uncomfortable, unsafe and hard to reach. In The Irish Times, a writer reported seeing a resident walk a catwalk 15 feet tall to reach his abode.

Although people have found ways to adapt to their living situations, just accessing home could be a dangerous enterprise.

8 They Elect A Mayor

It’s hard to believe underground communities would organize, let alone create rules. Yet according to The Los Angeles Times, a community of 145 people living under New York City actually elected a mayor.

There are even other jobs people have, like looking for more supplies and keeping a watch over their territory.

7 They Still Can’t Fully Escape The Rain

When it rains, it’s better to be underground than on the streets. While this thinking is what motivates many to go below the surface, they can’t escape the rain completely.

In a story by Narratively, one reporter noted rain falling through vents to the world below. Even mother nature has a way of finding its way to the tunnels below a city.

6 They Know The Time Based On Trains

There’s no reason to own a watch or a sundial underground when there are trains on regularly scheduled routes to listen for.

NY Post reports that one underground resident uses the trains to tell him what time it is. The resident, who goes by the name Travolta, told NY Post, “After the 11:45 [p.m], I can sleep soundly until 7:15.”

5 They Take On Titles And Nicknames

Living underground gives many the chance to start over. Being its own world down there, many feel empowered by their surroundings and newfound liberties they didn't have before.

One underground dweller named Bernard Isaacs took on the title “Lord of the Tunnels” (The Irish Times). Who’s to say he can’t go by that name underground?

4 There’s Hot Water and Electricity

It’s surprising what some people living under New York City actually have access to. Narratively notes that Jennifer Toth’s book, “The Mole People,” claims people had hot water and electricity.

It’s worth noting that the book has critics who called out many of the claims Toth wrote about regarding secret tunnels and passageways below ground.

3 They Form Tribes

One of the popular sites “mole people” gathered too early on was the Riverside Park tunnel in New York. There were only a handful of people to start with, according to Narratively, until it grew populated enough to organize into tribes.

Even though people wanted to escape a traditional life, some of their practices mimicked the world above.

2 They Are Hospitable

Even though underground communities split off from the surface, people remain friendly. A writer for The Irish Times visited a resident in his small home.

Not only did the man openly welcome the other into his space, even lowering a ladder down to him, but played music on his flute.

1 It's Cold Where They Live

Living underground isn’t warm and comfortable. It can get really cold for residents, especially during the winter. A writer for The Irish Times even mentioned how he’d get sweaty just walking through the tunnels while feeling cold at the same time.

These low temperatures are the norm for underground dwellers.

Sources: Los Angeles Times, The Guardian, Untapped Cities, Narratively, NY Post, The Irish Times