This is a Bonus Cache.
The cache is not at the given coordinates. To find the final coordinates you must complete an Adventure Lab: A short walk around the fortress
By clicking on the image above you can see what Adventure lab is. You need to download the application on your phone.
By scanning the QR Code below you can start the adventure (in five steps), and at the end you will receive the cache coordinates.
Due the last feedbacks I checked the 4th stage. Really is hard to read the name on the bust, therefore I changed the question.