Qui regna il silenzio.

The sentence is:

• Qui = here
• regna = reigns / rules
• il silenzio = the silence

Grammatically, the subject is il silenzio, even though it comes after the verb. So the structure is:

• adverb + verb + subject

This is perfectly natural in Italian, especially in descriptive or literary-style sentences.

Because the subject is il silenzio, which is singular.

Even though il silenzio comes after the verb, it is still the subject of the sentence. Italian verbs agree with the subject, not with the position of the noun.

• il silenzio regna = silence reigns
• therefore: Qui regna il silenzio

If the subject were plural, the verb would be plural too:

• Qui regnano la pace e il silenzio = Here peace and silence reign

Italian often allows more flexible word order than English.

A more straightforward order would be:

• Il silenzio regna qui

But Qui regna il silenzio sounds more natural and expressive in many contexts. It gives prominence to qui and creates a descriptive effect, almost like painting a scene:

• Here, silence reigns.

This kind of inversion is common with place expressions like qui, lì, in questa stanza, ovunque, etc.

Italian uses the definite article much more often than English.

Here, il silenzio does not necessarily mean one specific silence in a narrow sense. It often refers to silence as a condition or atmosphere. Italian commonly says:

• regna il silenzio
• torna il silenzio
• nel silenzio della notte

Using il makes the phrase sound natural and idiomatic.

If you said just silenzio here, it would sound incomplete or unnatural in this structure.

The infinitive is regnare.

Its basic meaning is to reign or to rule, as with a king or queen:

• Il re regna da molti anni = The king has reigned for many years

But it is also used metaphorically, especially in descriptive language:

• regna il caos = chaos reigns
• regna la pace = peace reigns
• regna il silenzio = silence reigns

So in your sentence, it is not about an actual ruler. It is a figurative way of saying that silence dominates the place.

It is understandable and fairly common, but in this figurative sense it can sound a bit elevated, descriptive, or literary.

For example:

• Qui regna il silenzio sounds vivid and expressive.
• Qui c’è silenzio is more neutral and everyday.
• Qui è tutto silenzioso is also more ordinary.

So yes, Italians do use regnare metaphorically, but it often has a slightly more dramatic or stylistic feel than the simplest alternatives.

Yes, you could.

Both qui and qua usually mean here. In many situations they are interchangeable.

Very broadly:

• qui can sound a little more precise
• qua can sound a little more informal or conversational

But in most everyday cases, the difference is small. Both are correct:

• Qui regna il silenzio
• Qua regna il silenzio

Yes. That is grammatically correct.

However, it sounds different in emphasis:

• Qui regna il silenzio focuses first on the place: here
• Il silenzio regna qui focuses first on silence

Italian often chooses word order to highlight what comes first. So the original version feels more natural if you are introducing or describing a location.

Not exactly, though the general idea is similar.

• C’è silenzio qui = There is silence here
• Qui regna il silenzio = Silence reigns here

The first is plain and neutral.
The second is stronger and more atmospheric. It suggests that silence dominates the place.

So the difference is mostly one of style and tone.

It is the present indicative of regnare, third person singular.

So:

• io regno = I reign
• tu regni = you reign
• lui/lei regna = he/she reigns

In your sentence, regna matches il silenzio, which is third person singular.

No, but putting it first is very natural.

You could also hear:

• Regna il silenzio qui
• Il silenzio regna qui

But Qui regna il silenzio is especially natural when setting the scene.

Italian often places words like qui, lì, adesso, oggi at the beginning when they provide the frame for the sentence.