Forced perspective is a framing technique that uses a foreground subject to give an image depth. To the observer, the image in the foreground is a strong visual clue that the camera (or the spectator) is far away from the subject when shooting.
In a video, you can use this trick to "install" a place by first drawing attention to a detail in the foreground, and then changing the focus to a building in the background. For example, you can shoot a "Hotel" sign from the side of the road and then refocus on the entrance, where the action will take place. This type of establishing shot is a great way to establish a mood instead of starting the video straight into the action. Think of the same sign under a rainstorm or, alternatively, under sunny skies with birds chirping.
This technique is also used to give the impression that a person is very small and can fit between the fingers of someone who is in the foreground of the photo or, as seen in the picture above, that a toy truck shares the road with other cars on the street.
Of course the more you prepare and look after details, the closer you can get to pulling off an actual illusion. You can see a master at work at http://petapixel.com/2013/10/14/life-like-miniature-scenes-shot-using-model-cars-forced-perspective-250-ps/