Until now we have seen only relative clauses whose relative pronoun refers to a single noun, be it a subject or an object. A relative clause can also specify a place or a time.

The place, where the accident happened, is known to be dangerous.
Der Ort, wo* der Unfall passierte, ist bekanntermaßen gefährlich.

* Many people believe that wo should not be used as a relative pronoun. That's not correct. Wo can be used as relative pronoun when referring to a place. This wrong opinion is caused by the fact that in Southern Germany wo is used as relative pronoun for whatever object. In Southern Germany you can hear quite often phrases like:
incorrect: Der Mann, der wo über die Straße läuft.
incorrect: Der Mann, wo über die Straße läuft.

This wo, even if it is used widely is incorrect. A lot of people who want to be over-over-correct criticise then the use of the relative pronoun wo in the whole. But we have to distinguish the use of the relative pronoun wo as a relative pronoun for places and times and the use as a relative pronoun for all objects.

Following phrases are correct:   Das Zimmer, wo er geschlafen hatte, war leer.   = The room, where he has slept, was empty.   Die Zeiten, wo man noch einkaufen konnte, was man wollte, sind vorbei.   = The times, when one could buy whatever one wanted, are over.   Nevertheless the following phrases are correct as well:   Das Zimmer, in dem er geschlafen hatte, war leer.   = The room, in which he has slept, was empty.   Die Zeiten, in denen man noch einkaufen konnte, was man wollte, sind vorbei.   = The times, in which one could buy whatever one wanted, are over.