Inversion

Inversion means putting the verb before the subject.
It is a literary technique in which the normal order of words is reversed, generally for emphasis
or special effect. It makes a sentence sound striking or unusual. It also sounds quite formal.
Sentences with inversion are less common in everyday English.
In a sentence with no special effect or emphasis, the normal order of words is retained.

Example 1 : I have never seen such a beautiful rose.
Example 2 : Never have I seen such a beautiful rose.

In example 2 inversion is used to emphasise the fact that in your whole lifetime
you have not seen such a beautiful rose.

It is sometimes difficult to remember when inversion is or can be used.
Here are some guidelines and examples to help you.

In normal everyday English, inversion is used :

To make questions : Does he?   Can you? After 'so' 'neither', 'nor' :  So do I, neither do I, nor do I. In written English, as well as in a very formal style, inversion can be used in the following cases : After negative adverbial expressions  : Under no circumstances can we accept credit cards. In no way can he be held responsible. At no time did she say she would come. Not until I heard my name did I believe I had won the race. After adverbial expressions of place : Round the corner came the postman. On the doorstep was a bunch of flowers. After 'seldom', 'rarely', 'never', and 'little' : Seldom have I seen such a beautiful view. Rarely did he pay anyone a compliment. Never had I felt so happy. Little did he imagine how dangerous it would be.