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.

The Burning Mountain of Dudweiler is not actually a mountain but a rocky ravine in the middle of a beech forest. Inside it, a coal seam caught fire and has been quietly smoldering for more than 300 years, with wisps of smoke escaping from the cracks in the rock.
To this day it remains unclear how the fire started. According to old accounts, a shepherd is said to have lit a fire against a tree stump, and a strong wind then drew the flames down through the roots into the surface coal.
A black plaque on the rock marks Goethe's visit in June 1770. When it gets colder outside, you can still see the steam rising from the fissures - and holding your hand into it, you can burn your fingers.
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.

Merzig
Dagstuhl Palace
The palace was built in the 18th century, with a beautiful chapel, a Stations of the Cross and a crypt to visit.

Merzig
Werner Freund Wolf Park
One of the world's largest wolf enclosures near Merzig, where researcher Werner Freund lived among several packs.