This center is the first and only astronomical center in Croatia that includes both an observatory and a planetarium as the digital planetarium is the only one of its kind, not only in Croatia, but also in the region. It is one of the few centers that can be reached by city bus and it is located at the top of Holy Cross Hill which is the oldest archaeological site in Rijeka, and it has been protected by the Cultural Heritage of the Republic of Croatia since May 2006. This project is the greatest investment in technical culture in Croatia . It had been used as a military fortress during World War II and was subsequently adapted.