Welcome to the peak of the Alta Murgia National Park. As you stand here, five hundred and forty meters above sea level, you are looking at one of the most mysterious and debated structures in human history. This is Castel del Monte, a masterpiece from the twelve forties commissioned by the Holy Roman Emperor, Frederick the Second. Unlike most medieval fortresses that were built for war, this building stands alone, isolated on its hilltop like a giant crown lost in the landscape. In nineteen ninety-six, the United Nations Educational, Scientific and Cultural Organization, also known as UNESCO, recognized it as a World Heritage site for its one-of-a-kind blend of cultural traditions. As you begin your walk toward the massive stone entrance, take a breath of the fresh Puglia air and notice how the light hits the white limestone walls. You are about to enter a world where mathematics and mystery meet in perfect symmetry.