From ancient temples to soaring cathedrals, humanity's deepest beliefs have given rise to sacred architecture. Rome's Pantheon, with its perfect dome and mysterious oculus, blends beauty and functionality in ways that puzzle modern architects to this day. Rising majestically from the sea, the gravity-defying Mont Saint-Michel reveals the extraordinary vision and skill of its builders, who overcame tides and challenging foundations to construct a monastery high on a rocky island. And the Porta Nigra, the best-preserved Roman city gate north of the Alps, finds its fate hanging in the balance until a Greek hermit's arrival transforms this military stronghold into a sacred sanctuary, ensuring its survival through the centuries.