Ľubovňa Castle was built after 1292 by the Hungarian King Andrew III. As a border guard castle, it protected trade routes to Poland. Famous Hungarian and Polish noble families entered its history. The castle was the seat of the Polish trustees from the Spiš region for more than 350 years. Hungarian and Polish Kings and Queens, such as Mary, Sigismund, Vladislav II Jagiełło, John Albrecht, John Casimir, John Sobieski, honored the castle by their visit. Between 1655 and 1661 Polish crown jewels were hidden in the castle. Today their replicas - crown, apple, scepter and coronation mantle of Stanislaw August Poniatowski are exposed in the castle chapel. Famous adventurer Moric Beňovský who eventually became the king of Madagascar got to know the castle prison in 1768. One of the most valuable objects of the castle is definitely the main castle tower (Nebojsa) which has been preserved since the medieval era. There is an outlook tower with 360 degree view of the surroundings on the sixth floor. Just below the castle there is a unique natural museum that is definitely worth visiting.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.