Porta Nigra

The fourth day of our short holiday at Saarburg we went to Trier.

Trier (French: Trèves, Luxembourg: Treier, Latin: Augusta Treverorum) is, together with Worms, one of the two oldest cities in Germany and also the oldest diocese north of the Alps.
And of course the main attraction is the Porta Nigra.
The Porta Nigra ("Black Gate") is made of sandstone and owes its name to the black layer on the stones caused by soot deposition in the Middle Ages.