Washington: The United States' Central Intelligence Agency (CIA) has revealed a challenge to test if people have the sharp eye and attention to detail needed to make it as an investigator.
Understandably, only the sharpest minds make it through the selection process for the agency which gathers and analyses security information from around the world.
The CIA's official Twitter account shared two photos of the same scene, challenging users to spot 10 small differences between the images including tiny differences only a select few managed to find.
The tweet read: "Put your observation skills to the test. Can you spot the 10 differences in the photo below? Check back tomorrow to see if you found them all."
Some obvious changes include a man not wearing a backpack, a missing person, a safety rail which has been removed and a car changing colour while smaller details included a light bulb changing from lit to unlit, and a small gold detail appearing on a building in the background.
But some spotted two extra minute details which had changed, such a line of paint missing from the archway of a tunnel on the left, and a badge being added to a car parked in the foreground of the image.