Perched on a sharp rocky spur of Záruby — the highest peak of the Little Carpathians — the castle ruins of Ostrý Kameň are a dramatic reminder of medieval border life. Built in the 13th century to guard the ancient 'Czech Road' trade route, this Gothic fortress at 576 m above sea level rewards every hiker with a powerful sense of history and wild natural beauty.

The setting is genuinely rugged. Limestone walls grow straight out of the bedrock, and dense forest presses in on all sides. In spring and summer the greenery is lush and atmospheric; autumn turns the hillside into a blaze of colour; and in winter, when the leaves fall, the skeletal ruins feel almost otherworldly. The rocky ridge is steep, and a moat cut directly into solid rock once separated the castle from the mountain ridge behind it — you can still see it today.

• Buková village (park in the village) — trail through the Záruby National Nature Reserve, moderate difficulty. The castle sits directly on the slopes of Záruby.

• The castle lies within the Záruby National Nature Reserve — stay on marked trails.
• The walls are in poor condition — take care when exploring the ruins.
• No tourist facilities on site (no car park directly at the ruins, no shelter).

From the castle's watchtower, guards could once spot three other castles simultaneously — Plavecký hrad, Korlátka and Branč — a testament to its strategic importance along the old trade route between Buda and Bohemia.