Lichtenberg Castle near Kusel
Admittedly this destination lies just outside the Saarland, but a visit is well worth it - one of the largest castle ruins in Germany.

Admittedly this destination lies just outside the Saarland, but a visit is well worth it - one of the largest castle ruins in Germany.
Attractions nearby

Saarbrücken
St. Arnual Dragon's Teeth (Westwall)
A 700-meter line of Westwall anti-tank obstacles on the Petersberg in Saarbrücken-St. Arnual - the final construction phase of 1940, now a listed monument.

Saarbrücken
The Burning Mountain near Dudweiler
Not really a mountain but a rocky ravine - a coal seam has been smoldering inside it for more than 300 years. Goethe visited the Burning Mountain in 1770.

Merzig
Dagstuhl Palace
A baroque palace of 1760 at the foot of the older Dagstuhl castle near Wadern, with a chapel holding a Stations of the Cross and a crypt. Since 1989 it has housed the Leibniz Center for Informatics.