About half way between Mainz and Cologne, the Moselle joins the Rhine at Koblenz.
It is 342 Miles (550 km.) long and rises near Col de Bussang in France, flows past Toul, Nancy, Metz and leaves France below Diedenhofen in Germany, where it forms the frontier of Germany and Luxembourg for a short distance.
Starting near Trier, the river meanders in an irregular zig-zag course in its lower valley, where the vineyards are and the well-known Moselle wines are produced.
The meandering of the river results in many peninsulas, some of them with villages on them and has given the area the name Die liebliche Mosel (The lovely Moselle).
Trier is the oldest city in Germany and was founded by the Romans about 15 B.C.
Trier is the centre of Moselle wine trade.
The most remarkable Roman building is the Porta Nigra, the fortified northgate of the city, 118 ft.(40 meters) long, 98 ft.(30 meters) high and 75 ft.(23 meters) deep, built of sandstone blocks. This building may date from the 3rd to 4th century A.D.
In 1035 Archbishop Poppo converted the gate into two churches, one above the other, but all the additions except the apse have been removed.
In the south-east of the city are ruins of 4th-century Roman baths (Imperial thermae).