3D movies used to be an entirely different story in the past than they are today because just like many things, these movies only get better with time. Some people still do not understand the difference between 3D movies of the past and those of today, so we will discuss a few things about these differences here, like how they used to work and how they work now. This should shed some light on the mystery of modern cinema.
3D movies used to work by taking advantage of what your brain is doing already. Really, this feature of 3D cinema has not changed, but the method is different. It used to be that you were shown two movies that were at slightly different angles at the same time. Your brain had to decide what to do about the problem so that you could see the movie clearly, and what it would do is tell you that what you were seeing was a actually depth. This was not true, but your brain had no idea.
One of the problems with the way that old 3D movies used to work is that it relied a lot on the colors of red and blue blocking out each other, hence the glasses that we all know and love. This meant that the movie makers were limited in the colors they could use because they had to rely on the cancelling out of colors for your brain to lie to you correctly.
Nowadays, 3D movies are made with a much higher quality than those of long ago before there was 3D TV even. It is still the same idea that your brain is going to create depth when it is shown different angles and movies at once. This is just what your brain does as long as you have two eyes, which not everyone does. If you do, you are lucky, one of the reasons being that you can enjoy 3D movies.
The 3D movies today take advantage of polarization, which the old movies did not. This means that when you have the red over one eye and blue on the other, it is not so much that the colors are what are doing the magic. It is that your eyes are each receiving different wavelengths because those glasses are blocking out one or the other. This leaves your eyes receiving two different images.
What does your brain do with these two different polarized images? You already know the answer: it creates 3D movies out of the situation! This allows you to enjoy the larger-than-life story while also perceiving it as having dimensions.
The main thing we have to thank for modern 3D movies and 3D blu-ray movies is polarization and the ever-developing knowledge of our brains and the way we perceive dimensions. Because people will always love cinema, there will always be more information about these processes so we can enjoy movies that feel more real than life itself sometimes.