Usually when someone finds a USB stick out in the wild and puts it into their computers, it spells trouble in the form of malware. This time around, the trouble is the sensitivity of the data the stick contains: Heathrow Airport’s security information.

Found by a man walking along a city street in Queen’s Park West London, the stick contained specifics about where CCTV cameras, tunnels, and escape routes are located. And, as Hilary McGann and Ralph Ellis report for CNN, it also held sensitive information such as the route the Queen takes when using the airport.

Read the full story on CNN.