14.04.2025

The art of invisibility

Disclaimer#

This guide is for informational purposes only. The author does NOT encourage any illegal activity. Always check local laws and regulations.

Navigating abandoned sites isn't just about watching your step around decaying structures but it's also about moving unseen and unheard. While many locations are truly forgotten, others might have unexpected occupants like squatters, other explorers, security, etc.

Mastering stealth and knowing how to react to encounters is just as crucial as spotting hidden cameras, motion detectors, or alarms. This guide covers both the art of staying hidden and the technology designed to detect you.

This blog post is split into three parts:

The art of invisibility
Handling encounters
Technological hurdles

1. The art of invisibility#

Moving through any site, abandoned or active, requires a level of stealth to avoid detection. Sound travels easily in empty buildings, and unexpected noises can attract unwanted attention.

Communication#

If exploring with others (recommended), use hand signals or whisper, don't shout.

Move Slowly and Deliberately#

Take your time, plan your steps, and be mindful of your surroundings.

Listen#

Pause frequently to listen for sounds within and outside the building – voices, footsteps, vehicles, machinery.

Watch Your Step#

Debris like broken glass, loose metal, or even dry leaves can make surprisingly loud noises when you step on them.

Gear & Clothing#

You already know from our last blog post about Essential gear for urbex adventures what you should bring with you and what not ;)

Plan B#

When exploring, you should always have a plan B ready.

First, try to act like you don't know that you were seen, and avoid suspicious behaviour like crouching, checking doors/windows, or looking around, etc.

If that doesn't work, you can try to act like you are lost or confused, and your last option should be to RUN.

2. Handling encounters#

Even the stealthiest explorer might encounter someone unexpectedly – be it security, workers, other explorers, squatters, or individuals seeking shelter. How you react can significantly impact the outcome.

Hearing someone coming#

This means you heard approaching footsteps, voices, or vehicle sounds. Since you have more time to react, it's better to hide.

This approach is indeed risky because if you are caught, you are really caught, but hiding for a little while should do the job, since no one will expect you to be there and they will most likely just mind their own business.

Always try to find a hiding spot that has multiple escape routes and ideally allows good observation of the environment - pay close attention to the person coming and try to find out whether they're searching trough rooms - in that case, you were probably somehow spotted and the person you hear is trying to find you - it's up to you to decide whether you try to leave stealthy or stay at your hiding spot and risk having an unpleasant hide-and-seek experience.

Sudden Appearance#

This is worse because you have little to no time to react, but first try anything but running. The first thing human eyes see is movement, the second is a person.

So just freeze, turn off your flashlight, cover your face with your hands or somehow disguise your silhouette, and listen and observe closely while you wait for them to pass.

If you are lucky and they didn't see you, you have an opportunity to leave unnoticed, hide, or continue your exploration.

On the other hand, if they saw you, it's up to you whether you want to test your social engineering skills or, again, RUN.

3. Technological hurdles#

We use technology in our daily lives, and it's everywhere. It's designed to help and protect us, but for urbexers, it can be quite a challenge.

Motion detectors#

This is probably the most common type of security system you will encounter.

They are common in active buildings but can sometimes be found guarding specific areas or entrances in less-used sites.

Types of motion detectors#

There are many types, like ultrasound, vibration, etc., but two of them are the most common.

1. Passive Infrared (PIR)#

These are the cheapest and very power-efficient. This makes them the most commonly used type. They take snapshots of the area every few seconds and compare them to detect motion.

2. Infrared + Microwave#

The second most common type, which is also more expensive. It basically does the same thing as PIR, but it's more sensitive and harder to fool.

If you find yourself in a situation with this type, then you are in a place where they are fairly serious about security.

How to spot motion detectors#

It's not that hard to spot them since their purpose is to detect motion, so they need to have line-of-sight, meaning you can see them too (if not hidden in some way, which is unlikely).

1. Look for the box#

Identify the small plastic housings (as you can see in the images above), often placed high up on walls or in corners for a wider field of view.

2. Key locations#

Look near important doorways, roof hatches, outside exits, tops and bottoms of stairwells, and areas leading to potentially valuable equipment or rooms.

3. Note the LEDs#

Some detectors have small LED lights that might blink or light up when detecting motion, even if the main alarm is off (like during the day). This can help you identify their range and sensitivity.

What happens when they detect motion#

Not all detectors are the same, some are there just to scare you away, some are there to get you caught.

1. Lights#

Some detectors only turn on the lights, and that's it. But you can't be sure if they aren't triggering a silent alarm at the same time.

2. Local Alarm#

A loud local alarm may be triggered instantly, or a countdown may start, after which the silent alarm is activated.

3. Silent Alarm#

Probably the worst-case scenario. The detector might silently notify security (on-site or remote).

If the security is on-site, they will probably come to check it out (and/or call the cops). If the security is remote, they will most likely just call the cops right away.

Alarms (Doors & Windows)#

Usually, there is not just one layer of security, but multiple layers. And again, there may be multiple types of alarms.

Types of alarms#

1. Magnetic reed switches#

Very common for doors and windows but can be found in other places too. They are designed to detect if the door or window is open or closed.

Again, they are connected to some alarm.

How to spot magnetic reed switches#

Look at the top or side edges of doors and windows and their corresponding frames. Check for small wires or thin metal conduits running near the frame, leading to the switch.

How to bypass magnetic reed switches#

Though in theory it's possible by using a magnet or unscrewing them and then binding them together, but this isn't the case in real life.

There are basically no perfect ways to bypass them. You can try your luck and hope that they are disabled since security and people working there are often annoyed by them.

2. Emergency exit alarms#

You can't miss them because they are usually followed by a big warning sign. All emergency exits are usually connected to an alarm so they can warn others in case of fire or other emergencies.

How to spot emergency exit alarms#

Because they are usually followed by a big warning sign, you can also spot them easily by their door handle, which includes a magnetic reed switch.

Cameras#

Last but not least, cameras. Yes, they are less common in truly abandoned buildings, but they can be on the streets or in other buildings. That's why it's important to be aware of them, know how to spot them, and most importantly, how to stay hidden from them.

It depends on where you live, but in most cases, you find warning signs about the presence of cameras.

Types of cameras#

1. Overt#

There is not much to say. They are designed to be seen and act as a deterrent. You can't miss those!

How to spot overt cameras#

They are usually mounted on ceilings or walls, and they are usually dome-shaped or have a big body.

It can be tricky to spot them at nighttime or in low-light conditions. They use infrared light (IR) to see in the dark that's invisible to the human eye, but not to your phone camera.

Try looking through your phone camera, and if you see a purple light, you are looking at an IR camera, aka night vision camera.

Remember to stay hidden, explore safely, and have fun!

Sources#

Reddit: Question about a motion detector/alarm
Reddit: Do they really add surveillance in abandoned buildings?
Deeterelectronics: Reed Switch How It Works

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