Virtual window in head-mounted display

Methods and systems involving a virtual window in a head-mounted display (HMD) are disclosed herein. An exemplary system may be configured to: (i) receive head-movement data that is indicative of head movement; (ii) cause an HMD to operate in a first mode in which the HMD is configured to: (a) simultaneously provide a virtual window and a physical-world view in the HMD; (b) display, in the virtual window, a portion of a media item that corresponds to a field of view; (c) determine movement of the field of view; and (d) update the portion of the media item that is displayed in the virtual window; (iii) receive mode-switching input data and responsively cause the HMD to switch between the first mode and a second mode; and (iv) responsive to the mode-switching input data, cause the HMD to operate in the second mode.