Modulations, key changes

In the majority of Queen songs we will find that the initially established key is changing during the song. For example "Teo Torriate" starts in d-minor, but the bridge is in D-Major. These modulations are usually easy to notice. A good songwriter can use modualtion as expressive tool making the song more interesting, opening a new window of harmony.
Based on the relation of the source and destination keys, we can creat different types of modulations. The most frequently used types of modulations we are going to examplify with many non-Queen examples.