Da lontano, il campanile illuminato sembra molto piccolo.

Da lontano means from far away, from a distance, or from afar.

It is a very common Italian expression:

• da vicino = from close up / nearby
• da lontano = from far away

Here it tells us the point of view: the bell tower looks small when seen from a distance.

Because da lontano is an established idiomatic expression in Italian. Even though lontano by itself means far or far away, after da it works naturally as from far away.

A native English speaker might expect a structure closer to from a distance, but Italian often prefers:

• da lontano
• da vicino

So this is just the normal way to say it.

Campanile means bell tower, usually the tower of a church containing bells.

It is a masculine noun:

• il campanile = the bell tower
• i campanili = the bell towers

English sometimes just says tower, but campanile is more specific.

Because illuminato has to agree with campanile, which is masculine singular.

Agreement here is:

• campanile = masculine singular
• so the adjective is illuminato

Compare:

• il campanile illuminato = the illuminated bell tower
• la torre illuminata = the illuminated tower

The ending changes to match the noun.

Here it functions as an adjective, even though it comes from the past participle of illuminare (to illuminate / light up).

So il campanile illuminato means:

• the illuminated bell tower
• the lit-up bell tower

This is very common in Italian: a past participle is often used like an adjective.

In Italian, descriptive adjectives often come after the noun.

So:

• il campanile illuminato = the illuminated bell tower

Putting the adjective after the noun is the most neutral, standard order here.

If an adjective comes before the noun, it can sometimes sound more literary, subjective, or emphatic, but campanile illuminato is the normal phrasing.

Sembra means seems or looks. It describes appearance, not an absolute fact.

So:

• è molto piccolo = it is very small
• sembra molto piccolo = it seems / looks very small

In this sentence, the idea is that from far away, the bell tower appears small.

Because the subject is already stated: il campanile illuminato.

Italian does not need an extra subject pronoun when the noun is present.

So:

• Il campanile illuminato sembra molto piccolo. = The illuminated bell tower seems very small.

Adding a pronoun would be unnecessary here.

Molto here is an adverb meaning very. It modifies the adjective piccolo.

So:

• piccolo = small
• molto piccolo = very small

This is just like:

• molto grande = very big
• molto bello = very beautiful

In this sentence, molto does not mean many or much as an adjective; it means very as an adverb.

Because after sembrare, Italian commonly puts the describing adjective after the verb:

• sembra piccolo = seems small
• sembra grande = seems big
• sembra interessante = seems interesting

So molto piccolo is the complement describing how the bell tower appears.

It is not always strictly necessary, but it is very natural.

The comma separates the introductory phrase Da lontano from the main clause:

• Da lontano, il campanile illuminato sembra molto piccolo.

Without the comma, the sentence would still be understandable:

• Da lontano il campanile illuminato sembra molto piccolo.

The comma just helps the rhythm and clarity.

Yes, that is also grammatical.

Both versions are possible:

• Da lontano, il campanile illuminato sembra molto piccolo.
• Il campanile illuminato sembra molto piccolo da lontano.

The version with Da lontano first gives more emphasis to the viewing condition: from far away. It sets the scene before the main statement.

In this sentence, because of sembra and da lontano, piccolo refers to appearance.

The bell tower may not actually be small. The sentence only says that it looks small from far away.

So the meaning is about visual impression, not necessarily real size.