Z samej góry widać jezioro i las.

Widać is an impersonal Polish form meaning you can see, one can see, or ... is visible.

So:

• Widać jezioro i las = You can see a lake and a forest
• more literally = A lake and a forest are visible

It is very common in Polish when the speaker wants to describe what is visible from a place, without saying exactly who is looking.

Because widać does not need one. It is impersonal.

English often uses a general you in sentences like this:

• From the top, you can see the lake

But Polish often avoids that kind of general you and simply uses widać. It sounds natural and objective, more like describing the view itself rather than the person viewing it.

The preposition z here means from, and when z means from/out of/off, it requires the genitive case.

So:

• dictionary form: góra
• after z: góry

That is why you get z góry or z samej góry, not z góra.

A useful comparison:

• z kolegą = with a friend → z meaning with takes the instrumental
• z domu = from the house → z meaning from takes the genitive

Here it is clearly the from meaning.

Here it is singular.

That can be confusing, because góry can be either:

• genitive singular of góra
• or nominative plural of góra

In z samej góry, it is genitive singular, because z requires that case here.

So this does not mean from the mountains. It means from the mountain / from the top.

Not in the English same sense.

In this sentence, samej means something like:

• very
• itself
• the very

So z samej góry means from the very top or from the mountain/top itself.

This use of sam is very common in Polish:

• na samym końcu = at the very end
• w samym środku = right in the middle
• od samego rana = from early morning / from the very morning

So samej here adds emphasis.

Because samej has to agree with góry.

The noun góra is:

• feminine
• singular
• here in the genitive

So the adjective must also be:

• feminine
• singular
• genitive

That gives samej.

So the structure is:

• z
  • samej
    • góry
• preposition + adjective in genitive + noun in genitive

It can suggest either, depending on context.

Góra can mean:

• mountain
• hill
• top / upper part

In this sentence, many learners will understand z samej góry most naturally as from the very top, especially because the sentence is about a view.

If the wider context is hiking or landscape, it may also feel like from the very top of the mountain.

So the exact English wording depends on context, but the Polish is perfectly natural.

They are functioning as the things that are visible, and with widać they are normally treated like a direct object, so they are in the accusative.

However, in this sentence their accusative forms look the same as their nominative forms:

• jezioro → nominative jezioro, accusative jezioro
• las → nominative las, accusative las for an inanimate masculine noun

So there is no visible change.

You can see the case more clearly with other nouns:

• Widać kobietę = You can see a woman
• Widać psa = You can see a dog

There the accusative ending is easier to notice.

Because Polish has no articles.

So jezioro can mean:

• a lake
• the lake

and las can mean:

• a forest
• the forest

Context tells you which meaning is intended.

That is why one Polish sentence can correspond to different English versions:

• From the very top, you can see a lake and a forest
• From the very top, you can see the lake and the forest

Both are possible depending on the situation.

Yes. Z góry widać jezioro i las is completely natural.

The difference is that samej adds emphasis:

• z góry = from above / from the top
• z samej góry = from the very top

So the version with samej sounds a bit stronger and more specific.

Yes, but the meaning shifts slightly.

• na samej górze means at the very top or on the very top and focuses on location
• z samej góry means from the very top and focuses on the viewpoint or source

So:

• Na samej górze widać jezioro i las sounds a little like at the very top, you can see a lake and a forest
• Z samej góry widać jezioro i las sounds more like from the very top, you can see a lake and a forest

Both can work, but z is very natural when talking about the view from a place.

Yes. Polish word order is flexible, and changing it mainly changes emphasis.

For example:

• Z samej góry widać jezioro i las
  This is a natural neutral order: first the viewpoint, then what is visible.

• Jezioro i las widać z samej góry
  This puts more focus on jezioro i las.

• Widać jezioro i las z samej góry
  Also possible, though the first version is usually the most natural as a plain description.

So the original sentence is a very good, idiomatic choice.