Head-direction cells fire when a mammal's head points in a specific direction in a horizontal plane and may provide 'compass' information to allow navigation, at least in two dimensions. Whether mammals possess a three-dimensional (3D) compass is less clear. Finkelstein et al. developed a device that tracked the head direction of behaving bats in 3D space and allowed neural recordings in the dorsal presubiculum, where head-direction cells are found. In crawling and flying bats, they found head-direction cells that were tuned to azimuth, pitch or roll, or combinations of these Euler angles, supporting a role for these cells in bat navigation in 3D space.