Learn Hardcore German: Die Richtung zum Park ist klar. - The direction to the park is clear.

Because Richtung is a feminine noun in German. The definite article for feminine nouns in the nominative case is die. Since Die Richtung zum Park is the subject of the sentence, it takes die in nominative.

What does zum mean, and why not just zu dem?

zum is the contracted form of zu dem. Here zu means “to,” and dem is the dative masculine article (the dative form of der). German frequently contracts zu dem → zum for smoother speech and writing.

Which case is Park in, and how do we know?

Park is in the dative case. The preposition zu always requires the dative. Since Park is masculine (der Park in nominative), it becomes dem Park in dative, hence zum Park.

Why isn’t klar written as klare or klaren?

Here klar functions as a predicative adjective (a complement to the verb ist), so it remains uninflected. Attribute adjectives (those directly before a noun) get endings like -e or -en, but predicative adjectives stay in their base form.

Why is klar placed at the end of the sentence?

German main clauses generally follow the Subject–Verb–(Object/)Complement order. In Die Richtung zum Park ist klar, klar is the predicate complement following the verb ist, so it naturally appears at the end.

Could you say “Die Richtung in den Park ist klar” instead? What changes?

You could, but it changes the nuance.

in den Park (accusative) suggests movement into the park.
zum Park (dative) suggests movement toward the park (its vicinity or entrance).
Since we’re talking about a path or orientation rather than entering, zum Park is more precise here.

Why is Richtung capitalized?

All German nouns are capitalized, no matter where they occur in a sentence. Richtung is a noun, so it’s always written with a capital letter.