-What you can expect- Discover the hidden gem of Istanbul, the Cistern of Theodosius. Beneath the bustling streets of Istanbul lies an ancient wonder, the Cistern of Theodosius (also known as the Serefiye Cistern). This remarkable structure showcases impressive engineering feats from centuries past. As you step inside, you'll be greeted by towering columns and a serene atmosphere that offers a glimpse into the city’s rich history. Constructed during the reign of Emperor Theodosius II (408-450 AD) and later expanded by the Ottomans, this cistern was ingeniously designed to store water, particularly during shortages or sieges. Its grandeur is highlighted by 32 marble columns sourced from Marmara Island, demonstrating the craftsmanship of its builders. With dimensions of 24 by 40 meters and a ceiling height of 11 meters, the cistern's robust structure is further reinforced by watertight plaster-coated walls and curved corners, designed to withstand pressure. The cistern also features 45 sail vaults, adding to its architectural splendour. As you navigate through this ancient wonder, an audio guide will provide fascinating insights into the history of the cistern named after Emperor Theodosius II. You'll learn how its surroundings have evolved over time. Today, the cistern offers a modern interactive experience with a state-of-the-art 360° projection mapping system. This immersive technology allows you to explore the history of the cistern and Istanbul’s water systems.