Many legends and stories have been told about the casemate-system of the Eger Castle. The key point in its development was the construction of a casemate-system under the castle, as this invisible line of defence played a crucial role in ensuring resupply and the defenders could sneak out of the castle without the attackers’ knowledge. The victory of 1552, the popular novel Eclipse of the Crescent Moon and the casemate-system all contributed to the mystery and esteem of the Castle of Eger, the most popular one in Hungary. The concept was to approach the new alternative route to the castle as an attraction but just as invisible as the casemate-system was. By utilising this unique underground tunnel system, it becomes a track starting in darkness, leading our way to above the city, composing the process of the ascent.