entlang: die Straße entlang

entlang (along) usually comes after the noun, with the Akkusativ:

• Gehen Sie die Straße entlang.
• Wir fahren mit dem Rad den Rhein entlang.

In written German it can also come before the noun, then mostly with the Genitiv: entlang des Flusses. For speaking, the position after the noun is the easy choice.