Learn Hardcore German: Der Höhepunkt des Tages war das Feuerwerk im Garten. - The highlight of the day was the fireworks in the garden.

The phrase Der Höhepunkt des Tages is in the nominative case because it’s the grammatical subject of the sentence. Within that phrase, des Tages is a genitive phrase that depends on Höhepunkt and means “of the day”.

Why is it des Tages and not des Tag or des Tags?

The base noun is der Tag (day). In the genitive singular, many masculine and neuter nouns add -s or -es:

der Tag → des Tages
der Hund → des Hundes / des Hunds
das Kind → des Kindes

Des Tages is the standard and most common genitive form of Tag.
You’ll occasionally see des Tags in older or poetic language, but in modern everyday German, des Tages is what you should use.

Why is des Tages in the genitive case instead of saying von dem Tag?

German can express possession or “of”-relationships in two main ways:

Genitive case:
- Der Höhepunkt des Tages = the highlight of the day
Von + dative:
- Der Höhepunkt von dem Tag (usually contracted: vom Tag)

The genitive (des Tages) is more compact and is considered more standard and a bit more formal or written-style.
Von + dative (vom Tag) is more colloquial and is very common in speech, but here Der Höhepunkt des Tages sounds more natural and idiomatic than Der Höhepunkt vom Tag in written German.

What case is das Feuerwerk in, and why is it also nominative?

Das Feuerwerk is also in the nominative case.

The verb sein (to be) is a linking verb (copular verb). In sentences with sein, both the subject and what it’s equated with appear in the nominative:

Der Höhepunkt des Tages (subject, nominative)
war (was)
das Feuerwerk im Garten (predicate nominative)

So both Der Höhepunkt des Tages and das Feuerwerk im Garten are in nominative, because they refer to the same thing from two perspectives: “The highlight of the day” = “the fireworks in the garden.”

Which part is the subject: Der Höhepunkt des Tages or das Feuerwerk im Garten?

Grammatically, the subject here is Der Höhepunkt des Tages, because that’s the first noun phrase and it “controls” the verb:

Der Höhepunkt des Tages war … → conjugates verb as 3rd person singular.

However, with sein, you can often switch the order without changing the basic meaning:

Der Höhepunkt des Tages war das Feuerwerk im Garten.
Das Feuerwerk im Garten war der Höhepunkt des Tages.

In both versions, the meaning is the same; German speakers normally treat the first noun phrase as the subject.

Could I also say Das Feuerwerk im Garten war der Höhepunkt des Tages? Is there any difference?

Yes, that sentence is perfectly correct:

Das Feuerwerk im Garten war der Höhepunkt des Tages.

The meaning is the same. The difference is in emphasis:

Der Höhepunkt des Tages war …
→ Puts focus on “the highlight of the day” and then answers what it was.
Das Feuerwerk im Garten war …
→ Puts focus on “the fireworks in the garden” and then characterizes them as the highlight.

Both are natural; which one you choose depends on what you want to emphasize first.

Why is it war (simple past) and not ist gewesen or war gewesen?

In German, both Präteritum (simple past) and Perfekt (spoken past) can describe past events:

Der Höhepunkt des Tages war das Feuerwerk im Garten. (Präteritum)
Der Höhepunkt des Tages ist das Feuerwerk im Garten gewesen. (Perfekt)

For many common verbs like sein, the simple past (war) is very frequent even in spoken German, especially in narrative contexts.
Ist gewesen is grammatically correct but sounds a bit heavier and is more typical when you really want to stress the completed nature of the event, or in certain dialects.

War is the most natural and neutral choice here.

What does im Garten mean exactly, and what is im?

Im is a contraction of in dem:

in (in) + dem (dative masculine/neuter) → im

Garten is masculine: der Garten (nominative).
After in (with a static location, not movement), German uses the dative case:

in dem Garten (dative) → contracted to im Garten

So im Garten means “in the garden”, and it’s dative because it describes location (where something was), not movement (where something is going).

Why are Höhepunkt, Tages, Feuerwerk, and Garten all capitalized?

In German, all nouns are capitalized, regardless of where they appear in the sentence. That includes:

Höhepunkt (highlight)
Tages (day, in genitive)
Feuerwerk (fireworks)
Garten (garden)

This is a standard orthographic rule in German and one of the big visual differences from English, where only proper nouns are capitalized (plus sentence-initial words).

What are the genders and articles of the nouns in this sentence?

The main nouns and their basic forms are:

der Höhepunkt (masculine) – “highlight, climax”
der Tag (masculine) → des Tages in genitive singular
das Feuerwerk (neuter) – “fireworks, firework display”
der Garten (masculine) – “garden, yard”

So, in the sentence:

Der Höhepunkt (nominative masculine singular)
des Tages (genitive masculine singular)
das Feuerwerk (nominative neuter singular)
im Garten = in dem Garten (dative masculine singular)

Can I drop the article and say Höhepunkt des Tages war das Feuerwerk im Garten?

You might occasionally see article-dropping in headlines or very telegraphic style:

Höhepunkt des Tages: das Feuerwerk im Garten

But in normal sentences, especially in spoken German or standard prose, you should keep the article:

Der Höhepunkt des Tages war das Feuerwerk im Garten.

Without der, it sounds like a headline or a note, not like a full, natural sentence.

What does Höhepunkt mean in usage? Is it like English “highlight”?

Yes, der Höhepunkt corresponds closely to English “highlight” or “climax”, depending on context:

Der Höhepunkt des Konzerts war das letzte Lied.
→ The highlight of the concert was the last song.
Der Höhepunkt des Films war die Verfolgungsjagd.
→ The climax of the film was the chase scene.

In everyday speech about a day, event, or trip, Höhepunkt is usually best translated as “highlight”.