This Baroque castle is undoubtedly the most prominent landmark of Saarbrücken. First mentions of a "Castellum Sarabrucca" date back to medieval times, but the city had seen several attacks and revivals until the building reached its current imposing presence. Today, it is home to various cultural events and the Invisible Jewish Memorial, made up of cobblestones engraved with cemeteries from all across Germany.

Inaugurated in 2001, this contemporary Islamic mosque is, perhaps, the capital's greatest attraction and largest place of worship. It features five minarets and room for 20,000 worshippers. The handwoven prayer hall carpet alone is a site to behold, its 1,700,000,000 knots took 4 years and 600 craftswomen to weave, and the carpet's total weight exceeds a staggering 21 tons.

Be prepared to have your mind bent, blown and rewired as you walk into the Lange Voorhout Palace where the illusory work of famous graphic artist M.C. Escher is exhibited. The palace is home to such legendary Escher paintings as 'Air and Water' in which birds are blended into fish and 'Waterfall' in which water appears to flow upwards instead of down. There are interactive experiences on the second floor, dedicated to the Eye of Escher where guests are encouraged to solve some of Escher’s most perplexing mysteries, including the impossible Penrose Triangle. On the third floor, there is a large-scale optical illusion where adults can appear to be children and vice versa. Audio tours and guided tours are available and there are additional temporary exhibitions taking place on occasion.