If a visitor walks through the royal town of Slaný today, he will come across only a few monuments that draw attention to the once monumental fortifications of the city, which are represented primarily by the still standing Velvar Gate. However, the massive medieval fortification consisted of an ingenious defense system including other protected entrances to the city (Lounská Gate, Prague Gate, fortna) and a double line of walls with a moat and many towers and bastions. However, most of the fortifications were demolished during the 19th century, and thanks to new technological possibilities, this application decided to make monuments that have already disappeared from the face of the earth accessible using virtual reality. A computer 3D reconstruction was created that represents what the town of Slaný looked like in 1602, when the famous Willenberg veduta was created. The application functions as a guide to the medieval appearance of the city, where a total of 8 stops were selected, where you can look directly into the past.