Airports work tirelessly to know everything that’s going on within their walls at all times. While sometimes the TSA‘s security efforts may upset everyday passengers, most people don’t know the half of what’s really going on in the background.

In fact, airports around the world are using a variety of new technologies to make it easier to keep tabs on people, both for security and for convenience. Here’s a look at all the way airports are using tech to learn everything about you when you set foot inside them.

Full Body Scanners
Probably the most well known “new technology” is the full body scanner. The most popular scanners used in airports use either X-Ray technology or “non-ionising waves.” They were first implemented to reduce lines at the airport, but recently the scanners have become more of a headache. The problem is that because anything out of the ordinary would trigger an alarm requiring an airport employee to perform a pat-down, these scanners have actually started making lines worse.

Iris Scanners
Airports are now using iris scanners to keep tabs on passengers. It isn’t as creepy as it seems, though. For instance, Gatwick Airport in London uses iris scanning technology to make getting through lines faster. The airport doesn’t differentiate between domestic and international passengers when performing security checks, but it does need a way to quickly distinguish between the two. So the airport has domestic passengers quickly scan their iris, and then, when they reach their gate, their irises are checked again to make sure they completed the boarding process and actually made it on the plane. Gatwick Airport tells Business Insider this has decreased wait time tremendously, and has made it a breeze for people in England to get from one city to another.

Smart Bag Tags
One problem airports face regularly is losing baggage. Now airports like Hong Kong International Airport are using RFID technology to track where bags go. The idea is that these tags use Bluetooth and other mobile technologies to give passengers real-time updates about where their bags are.

Height Profiling
Height profiling is another interesting technology. Using stereoscopic cameras in the ceiling, these devices track people based on their body makeup. It knows how tall people are, how far their shoulders are from their head, and other size comparison, and it uses this data to understand people’s movement patterns. It also keeps profiles on the other people you are walking with, so if you tie your shoelaces (thus changing your height profile), it will assume you’re still there because the people around you are still there. This isn’t used to always know where you are, however, it’s used for research. Gatwick Airport — which is trialing it — wants to know how long it takes passengers to go through security. This technology gives the airport real-time data about who is moving, how fast, and what is causing a congestion. And it doesn’t give specific information about who the passenger is.

Facial Recognition
Airports have been toying with the idea of facial recognition technology for years. Now, according to Motherboard, the Customs and Border Protection at Washington DC’s Dulles Airport is implementing an experimental facial recognition program. This, however, is being met with concern from privacy advocates, as the intent is to use biometric technology to catch people who are using others’ passports.

Fingerprint Scanning
Keeping with biometrics, some airports are using fingerprint scanning technology. Baltimore-Washington International Thurgood Marshall Airport, for instance, is implementing a new system that lets passengers check in using their fingerprint. It — like Gatwick’s iris scanning program — is being implemented in the hopes of reducing lines and congestion.

The Department of Homeland Security is looking into a new technology called “screen-and-walk.” It is a means to detect if passengers are carrying a concealed device on their person without having them take off their garments. The hope is to have a technology that is both fast and effective. DHS is still working to build this machine, but it’s been soliciting private contractors and tech companies to further its development.

Beacons have been used by marketers for the last few years as a way for retailers to engage with customers on mobile devices in real time using location. Now airports are following suit as a way to send up-to-the-minute information about flights and in-house attractions.

Augmented Reality
Like beacon technology, some airports have been looking into augments reality. Airports — such as the Copenhagen Airport — have been testing out mobile apps that use GPS to push content passengers. Content includes directions for how to get to the gate, as well as interesting attractions they may wish to see.

The MagRay is a device being tested in laboratories to detect the contents of a liquid. The idea is to combine an X-Ray and MRI to detect if the properties are different from a normal liquid. It’s still being tinkered with in labs, but it could make packing liquids and getting them through security that much easier.