Want to see how well your city knowledge stacks up? iJRD is an iPhone app designed to help researchers at the University of Pennsylvania learn about how humans navigate in a real-world setting. iJRD is currently available to people living in a number of cities around the world. To find out if iJRD is currently available in your city, download the app or go to spatialcognitionapp.com. If you choose to participate with iJRD, you can learn about how your spatial abilities compare to other people around the world.