1. An apparatus for implementing walkthrough display by displaying a plurality of image data held on a network in turn, comprising: an acquisition unit which acquires image data of a first landscape from the network; a display unit which displays the image data of the first landscape together with pointer information that suggests a direction of presence of a second landscape which has a geographical relationship with the first landscape; a detection unit which detects an input to the pointer information; and a control unit which, upon detection of the input, controls said acquisition unit to acquire image data of the second landscape from the network and controlling the display unit to display the acquired image data.