A 3-D (or three-dimensional) film is one that has a form or appearance giving the life-like illusion of depth, often achieved by viewers donning special glasses. When 3-D images are made interactive so that users feel involved with the scene, the experience is sometimes called virtual reality. 3-D broke on the scene and was quite popular in the 1950s and has more recently -- as of 2009 -- been seeing a resurgence as new technologies are coming to market and filmmakers such as James Cameron are embracing these new technologies.