Devín is now in ruins. Napoleon set off explosives under the castle during his retreat in the early 1800s. His reasoning for doing so is unknown.
Devín Castle is built on a historically rich plot. Settlements in this area trace back to the Neolithic Age. The Celts and Romans also settled here and it seems to have always been thought of as a strategic location. One can see why it would be considered strategically important. It borders two rivers, the Danube and the Morava, where they intersect. It also provides a great view of the surrounding area, making it advantageous.
The pictures above and below provide a spectacular view of Austria as well as the Danube itself.