Steam Train Katwijk Leiden

Tourist attraction Roman-built marl quarry with walking & tram tours through its art-filled underground passages. Tourist attraction Remains of a 12th-century hilltop fort above a labyrinth of passageways used as a refuge in WWII. Tourist attraction Hillside activity center with 2 long, twisting toboggan tracks & a drag lift back up the slope. Castle Ruins of a hilltop castle built in the 14th century at the site of even older fortifications. Tourist attraction Underground marl cavern with sculptures & fossils, plus rock-carvings & guided tours.