Learn Hardcore German: Im Wohnzimmer steht jetzt ein kleiner Kamin, den alle bewundern. - There is now a small fireplace in the living room that everyone admires.

Im Wohnzimmer steht jetzt ein kleiner Kamin …
The meaning is “in the living room (already there, as a location) a small fireplace is standing …”
So we use Dative: in dem → im Wohnzimmer

If it were movement into the living room, you would say:

Wir bringen den Kamin ins Wohnzimmer.
(ins = in das, accusative → direction: into the living room)

Why is it ein kleiner Kamin and not einen kleinen Kamin?

Because ein kleiner Kamin is the subject, not the object.

The verb stehen here means “to stand (be positioned)” and it does not take a direct object in this sentence.
So the thing that steht (stands) is the subject in the nominative case.

Nominative masculine singular with ein:

ein kleiner Kamin (subject; nominative)
If it were the object, you would have accusative: einen kleinen Kamin

Compare:

Ein kleiner Kamin steht im Wohnzimmer.
(A small fireplace is standing in the living room.) — nominative
Ich sehe einen kleinen Kamin im Wohnzimmer.
(I see a small fireplace in the living room.) — accusative

Why does the adjective end in -er: ein kleiner Kamin?

This is a nominative masculine singular noun with an indefinite article (ein), so the adjective takes the ending -er.

Pattern for ein + adjective + masculine noun, nominative:

ein kleiner Kamin
ein alter Tisch
ein neuer Computer

Quick rule of thumb:
For masculine nominative with ein, the adjective ends in -er.

What is the function of den in den alle bewundern?

Den is a relative pronoun that:

refers back to ein kleiner Kamin
introduces the relative clause den alle bewundern
stands for “which/that” in English

Grammatically:

Kamin is masculine, singular.
Inside the relative clause, den is the direct object of bewundern:
- Wer bewundert? → alle (subject)
- Wen bewundern alle? → den (direct object, accusative)

So we need the masculine accusative form of the relative pronoun:

Masculine nominative: der (e.g. der Kamin, der …) – if it’s subject in the clause
Masculine accusative: den (e.g. der Kamin, den …) – if it’s object in the clause

Here it’s object → den.

Why is there a comma before den alle bewundern?

Because den alle bewundern is a relative clause. In German, relative clauses are always separated by commas.

Structure:

Main clause: Im Wohnzimmer steht jetzt ein kleiner Kamin
Relative clause: den alle bewundern

The relative clause gives extra information about the noun Kamin:

… ein kleiner Kamin, den alle bewundern.
… a small fireplace which everyone admires.

So you always write a comma before the relative clause.

Why does the verb bewundern come at the end of den alle bewundern?

Because den alle bewundern is a subordinate clause (specifically, a relative clause).
In German subordinate clauses, the conjugated verb goes to the end.

Pattern:

Main clause: verb in second position
- Alle bewundern den Kamin.
Relative clause: verb at the end
- … den alle bewundern.

Word order inside the relative clause:

den (relative pronoun, object)
alle (subject)
bewundern (verb at the end)

Why is it den and not ihn in the relative clause?

Den is a relative pronoun, ihn is a personal pronoun.

den → means “which/that” referring back to Kamin and introducing a relative clause:
- … ein kleiner Kamin, den alle bewundern.
  … a small fireplace which everyone admires.
ihn → means “him/it” and does not introduce a clause:
- Alle bewundern ihn.
  Everyone admires him/it.

So after a comma, when you want “which/that …”, you must use a relative pronoun like der, die, das, den, dem, not a personal pronoun like er, sie, es, ihn.

Could I also say … ein kleiner Kamin, der alle bewundern?

No, that would be incorrect.

Inside the relative clause, you must choose the pronoun form based on its grammatical role there:

Wer bewundert? → alle (subject, nominative)
Wen bewundern alle? → den (object, accusative)

So you need accusative → den, not nominative → der.

Correct options:

… ein kleiner Kamin, den alle bewundern. ✔
(… a small fireplace that everyone admires.)

Wrong:

… ein kleiner Kamin, der alle bewundern. ✘
(Here der would be subject, but the subject is alle, so this doesn’t fit.)

Can I replace den with welchen in this sentence?

In theory, yes:

… ein kleiner Kamin, welchen alle bewundern.

This is grammatically correct, but:

welchen sounds more formal and old-fashioned in modern everyday German.
den is much more common and natural in spoken and standard written German.

So prefer:

… ein kleiner Kamin, den alle bewundern.

Why is alle used without any article: den alle bewundern?

Here alle is a pronoun meaning “everyone / all (people)”. As a pronoun, it stands on its own and does not need an article.

alle = everyone / they all
Subject of the relative clause: alle (who admires the fireplace? → everyone)

Examples:

Alle kennen ihn. – Everyone knows him.
Alle mögen das. – Everybody likes that.

If alle comes directly before a noun, it behaves more like a determiner:

alle Leute – all people
alle Kinder – all children

What exactly does bewundern mean here?

Bewundern means “to admire” (to look at something with appreciation, enthusiasm or respect).

alle bewundern den Kamin
→ everyone admires the fireplace
(they think it looks great, impressive, beautiful, etc.)

It is a regular, transitive verb:

Infinitive: bewundern
3rd person plural: sie bewundern
Past: sie bewunderten
Perfect: sie haben … bewundert

Why is steht used instead of ist? Could I say Im Wohnzimmer ist jetzt ein kleiner Kamin?

You can say:

Im Wohnzimmer ist jetzt ein kleiner Kamin.

This is grammatically correct and understandable.
However, steht gives a slightly more specific image:

ist – neutral existence: there is now a small fireplace in the living room
steht – emphasizes position / being placed upright:
a small fireplace is now standing/placed in the living room

German often uses stehen/liegen/sitzen (stand/lie/sit) instead of just sein (to be) when describing where objects are located.

Can I change the word order to Ein kleiner Kamin steht jetzt im Wohnzimmer, den alle bewundern?

Yes. That is perfectly correct:

Ein kleiner Kamin steht jetzt im Wohnzimmer, den alle bewundern.

Differences:

Original: Im Wohnzimmer steht jetzt ein kleiner Kamin, den alle bewundern.
- Focus starts on the place (living room).
Alternative: Ein kleiner Kamin steht jetzt im Wohnzimmer, den alle bewundern.
- Focus starts on the new object (a small fireplace).

Both sentences are grammatically fine; the choice affects emphasis and flow, not correctness.