CGI

If you've ever seen a black and white film, the most notable characteristics would be the low-quality audio without the fancy editing we have nowadays, and the dodgy props for action or thriller-based movies. In a sort of paradoxical way the scenes seem less believable with the real, tangible props than the CGI, or computer generated imagery used on screen in modern films - imagine live-action Disney movies, or the Lord of the Rings series without its fantasy elements added on screen.
 
Of course, CGI's use is not limited only to entertainment purposes: 

• It is also used to create 3-dimensional architectural models for projects which can be applied to the real world. Some modern architects even use CGI to try to "reverse engineer" famous historical buildings, e.g. ruins of a monastery in Germany were used to recreate a computer-generated likeliness of it in its time.
• Models of the human body can be visualised using CGI to be studied in the field of medicine, or even used for specific patients to plan surgeries by using data from CT scans or MRI's.
• CGI can also be used to generate very specific details in images which cannot be emulated by hand, such as wrinkles or skin pores. This type of fine detailing also extends to clothing and textiles with the structure of certain materials and is often used by fashion designers.

At any rate, the use of CGI has been pivotal in the technological movement of our modern era through pretty much any on-screen images we see daily and will probably continue to impact our lives in a big but subtle way.