Schlossberg Caves Homburg

Yellow, ochre, rust-red: in the Schlossberg Caves in Homburg, coloured bands swirl across walls and ceilings as if someone had pasted marbled paper inside the hill. Yet water did not shape these passages and halls, people did. Over centuries miners dug out sand here and left behind a labyrinth of twelve levels covering an area of about 140 by 60 m. According to the town of Homburg, they are the largest red sandstone caves in Europe.

History: sand, fortress and bunker

Red sandstone does not form karst, so natural caves of this size cannot develop in it. People probably dug escape tunnels for the Hohenburg castle on top of the hill as early as the early Middle Ages. Later the soft, quartz-rich sand itself became the resource: first for glassmaking, then as scouring sand and as moulding sand for the iron industry. A mine is first recorded in 1671.

When King Louis XIV had his military engineer Vauban turn Homburg into a fortress, the caves served as a storehouse. In 1708 a French engineer officer described damaged tunnels and spoiled supplies of ammunition and food. The caves were filled in by official order in 1872, and sand mining ended after a survey in 1893. They were only rediscovered in 1932, and during the Second World War local people sheltered here from air raids.

In the early 1950s the Saarland government under Johannes Hoffmann secretly had a bunker built in the lower nine levels. To disguise the work, today's Schlossberghotel was built on top at the same time. When Hoffmann resigned in 1955, work on the bunker stopped.

What to see

• Throne Room: The largest hall, with circular yellow-and-red patterns on the ceiling. Large amounts of sand came loose here in 2003, and the caves were closed for years afterwards.
• Ripple marks: Wave-like patterns on the ceiling show that the sand was laid down by wind and water more than 200 million years ago, in the Triassic.
• Mining traces: On many walls you can still see where miners scraped out the sand.
• Steel supports: Areas at risk of collapse are secured with steel frames installed during the restoration that began in 2003.
• Bunker section: The 1950s rooms adjoin the sandstone halls and are part of the guided route.

Good to know

The colours come from iron: red layers contain more of it, while the yellowish sandstone is about 95 percent quartz. Since the restoration, the caves have been classed as a show mine and fall under mining law. The tenth level reopened first in 2007, followed later by levels 11 and 12. A 30 m shaft also links the caves to a tunnel of the Karlsberg brewery.

Visiting and timing

The caves stay at 10 °C all year with 80 to 90 percent humidity, so bring a jacket even in summer. Allow about an hour for the tour. Information is available in German, English and French. Groups of ten or more should book ahead and can arrange a guided tour.

Tickets and opening hours (as of October 2026)

• April to October: 09:00–17:00, last entry 16:00
• November to March: 10:00–16:00, last entry 15:00
• Closed: December and January
• Admission: adults €7, reduced €5, families €17
• Combined ticket with the Roman Museum Schwarzenacker: adults €10, reduced €7, families €25

Payment is cash only; cards are not accepted.

Getting there

The entrance is on Schlossberg-Höhen-Straße on the Schlossberg above Homburg town centre. Above the bunker section stands the Schlossberghotel, built to disguise the construction work. The Roman Museum Schwarzenacker is only a few kilometres away and fits well into the same day with the combined ticket.