Learn Hardcore German: Wir gehen morgen in die Stadt, zum Beispiel in die Bibliothek. - We are going to the city tomorrow, for example to the library.

Accusative (Wohin? – where to?) = movement into something
→ in die Stadt = to (into) the city / into town
Dative (Wo? – where?) = location, no movement
→ in der Stadt = in the city / in town

In your sentence, you are going (movement) to the city, so German uses the accusative: in die Stadt.
If you were already there, you’d say:

Wir sind in der Stadt. – We are in the city.

Why is there a comma before zum Beispiel?

Here, zum Beispiel in die Bibliothek is an extra piece of information, like an aside: for example, to the library. German usually separates such parenthetical additions with a comma.

You could think of it as:

Wir gehen morgen in die Stadt, (zum Beispiel in die Bibliothek).

So the comma marks zum Beispiel in die Bibliothek as a kind of parenthetical comment that specifies an example of where in the city you might go.

What does zum Beispiel literally mean, and is zu dem Beispiel also possible?

Literally:

zu dem Beispiel → to the example
This contracts to zum Beispiel (zu + dem = zum).

However, in actual usage zum Beispiel is a fixed expression meaning “for example”. You should basically always use zum Beispiel, not zu dem Beispiel, when you mean for example.

You might encounter zu dem Beispiel in other contexts (e.g. “go to the example in the book”), but that’s quite rare and usually phrased differently anyway.

Why is there no verb after zum Beispiel? Shouldn’t there be something like gehen?

The second part zum Beispiel in die Bibliothek is elliptical – it leaves out words that are understood from the first clause.

Fuller versions would be:

Wir gehen morgen in die Stadt, wir gehen zum Beispiel in die Bibliothek.
Wir gehen morgen in die Stadt, zum Beispiel gehen wir in die Bibliothek.

Because you already have gehen in Wir gehen morgen in die Stadt, it doesn’t need to be repeated. Native speakers very often drop repeated verbs like this when the meaning is clear.

Can I also say Wir werden morgen in die Stadt gehen to express the future?

Yes, that’s grammatically correct and means the same in most contexts.

Wir gehen morgen in die Stadt. – Present tense + time word (morgen)
Wir werden morgen in die Stadt gehen. – “Futur I”

German prefers the present tense with a time expression for future actions, especially in everyday speech and writing.
The Futur I form (werden … gehen) is used:

when you want to sound more formal or explicit, or
for emphasis/nuance (e.g. predictions, assumptions).

In everyday conversation, Wir gehen morgen in die Stadt is more natural.

Could I say Wir gehen in die Stadt morgen instead of Wir gehen morgen in die Stadt?

You can, and people will understand you, but it’s less natural.

In German, there’s a common order rule often taught as:

Time – Manner – Place

So adverbs of time normally come early in the middle field of the sentence:

Wir gehen morgen in die Stadt. ✓ (very natural)
Wir gehen in die Stadt morgen. ~ (possible, but feels a bit marked or poetic/emphatic)

Putting morgen at the end might sound like you’re stressing tomorrow in a special way.

Why is it in die Stadt and not zur Stadt?

Both in and zu can express going to a place, but they’re used differently:

in die Stadt literally means into the city, and is the normal idiomatic way to say “go to town/go into the city”.
zu(r) Stadt would sound unusual or wrong in most contexts. zu is typically used with:
- people: zu meiner Freundin (to my girlfriend)
- institutions/activities: zur Schule, zum Arzt, zur Arbeit
- some places as “destinations”: zum Bahnhof, zum Park (depending on nuance)

For “going to town”, native speakers simply say in die Stadt (gehen/fahren).

What’s the difference between Stadt, Stadtzentrum, and Innenstadt?

All relate to “the city”, but with different focuses:

die Stadt
- General word for the town / the city.
- in die Stadt gehen is like English “go into town” or “go into the city” – usually implies the central area (shops, cafés, etc.), not just any random part.
das Stadtzentrum
- Literally city center; a bit more formal or neutral.
- Often used in signs, tourist info, directions.
die Innenstadt
- Means inner city / downtown; typically the central, often older or shopping district.

In everyday conversation, in die Stadt is the most common way to mean “go into town”.

Why is it in die Bibliothek and not in der Bibliothek?

Same logic as with Stadt:

in die Bibliothek (accusative) → movement: Where to?
- Wir gehen in die Bibliothek. – We are going to the library.
in der Bibliothek (dative) → location: Where?
- Wir sind in der Bibliothek. – We are in the library.

Because the sentence describes going somewhere, German uses the accusative after in.

Both Stadt and Bibliothek use die. How do I know they’re accusative and not nominative?

For feminine nouns, die looks the same in nominative and accusative singular:

Nominative: die Stadt, die Bibliothek
Accusative: die Stadt, die Bibliothek

So you can’t tell from die alone. You must look at:

The role in the sentence
- Subject (does the action) → nominative
- Direct object (receives the action) → accusative
The preposition
- in
  - movement (Wohin?) → accusative
- in
  - location (Wo?) → dative

Here, in die Stadt / in die Bibliothek are destinations with movement, so they are accusative objects of the preposition in, not the subject of the sentence. The subject is Wir.

What’s the difference between gehen and fahren in a sentence like this?

Both translate as “go” in English, but they’re used differently:

gehen = to go on foot, to walk
- Wir gehen morgen in die Stadt.
  → Either literally we’re walking into town, or more loosely “we’re going into town” (mode of transport not specified, especially in casual speech).
fahren = to go by vehicle (drive, ride, travel)
- Wir fahren morgen in die Stadt.
  → We’re going into town by car, bus, train, bike, etc.

If you want to be precise:

on foot → gehen
by some vehicle → fahren

In practice, spoken German often uses gehen more loosely, just like English “go”.

Is Wir gehen morgen in die Stadt, zum Beispiel die Bibliothek correct without repeating in?

That version sounds wrong or at least very odd to native speakers. You almost always need the preposition in again:

Wir gehen morgen in die Stadt, zum Beispiel in die Bibliothek. ✓

In German, when giving examples of locations with prepositions, you usually repeat the preposition:

Wir fahren nach Italien, zum Beispiel nach Rom.
Wir gehen in die Stadt, zum Beispiel in die Bibliothek.

Leaving out in before die Bibliothek doesn’t feel natural here.

Could I say Wir gehen morgen in die Stadt, zum Beispiel in eine Bibliothek?

Yes, that is grammatically correct, but it changes the nuance slightly:

in die Bibliothek
- Suggests a specific library that both speaker and listener likely have in mind (e.g. “the city library”).
in eine Bibliothek
- Means some library or other, not a specific known one.

In the original sentence, in die Bibliothek is usually understood as “the library in town that we typically mean”.