ISTANBUL: Beneath the magnificent structure of Hagia Sophia, an architectural masterpiece, a vigorous excavation and restoration effort is underway to reveal its long-hidden underground tunnels and passageways. Soon to be opened to visitors for the first time, these subterranean spaces promise to deepen the public’s understanding of the complex, multilayered beauty upon which the iconic building stands. Professor Hasan Fırat Diker, a member of the Hagia Sophia Scientific Committee, highlights how this discovery will enrich appreciation for the monument’s architectural and historical significance.
Constructed between 532 and 537 A.D. under the command of Emperor Justinian I, Hagia Sophia remains one of the most important edifices in architectural history. Serving as a church until Mehmed the Conqueror’s conquest of Istanbul in 1453, the structure has captivated onlookers for centuries with its massive dome and exquisite architectural elegance.
Inside, visitors are enchanted by stunning mosaics, intricate tiles, calligraphic panels, icons and ornate lamps. Highlights include the majestic Imperial Door and the marble circle known as the Omphalion – the ceremonial coronation area that adds to the building’s aura of grandeur.
Yet beyond these celebrated interiors, it is the fine details – often centuries old – that evoke profound admiration. Plans are now underway to open Hagia Sophia’s subterranean levels to the public. For years, these underground tunnels and chambers lay concealed beneath layers of rubble and soil. Thanks to ongoing restoration efforts led by the General Directorate of Foundations, these passageways are gradually being cleared, revealing their true extent and complexity. As cleaning progresses, previously unknown tunnels have come to light, expanding the scope of this extraordinary network.
The goal is to open these underground spaces to visitors in the near future, allowing people to explore a hidden world beneath the historic monument. Diker shared insights into this mysterious realm, emphasizing the project’s significance for architecture and archaeology.
The exploration started in earnest in early 2021 following a 3D infrastructural survey completed in 2020, supported by the Ministry of Culture and the General Directorate of Foundations. Significant progress has been made since then, and the project is expected to substantially enrich our understanding of Istanbul’s unseen architectural treasures.
As the underground structures are interconnected through a complex network of tunnels, the team has discovered new chambers and passages previously inaccessible or unknown. Although not all areas are safe or suitable for visitors, sizable accessible sections will be opened, providing a rare glimpse into this hidden world.
One of the largest underground areas lies beneath what was once a colonnaded courtyard in the 18th and 19th centuries – now lost to time. Due to the sloped terrain, this basement served practical purposes. Today, these subterranean spaces beneath the vanished courtyard are among the easiest to reach. Additionally, on the northeast façade, archaeologists uncovered an underground tomb predating Hagia Sophia itself, distinguished by its unique architecture and distinctive two-tone marble flooring. This tomb connects through a labyrinth of tunnels circling the base and surroundings of Hagia Sophia.
Many of these tunnels historically served practical functions, such as housing terracotta water pipes for the building’s supply and drainage systems. The passages were narrow, often requiring crawling to navigate, and were designed primarily for maintenance rather than leisurely exploration. They also facilitated ventilation, enabling air circulation between the interior and exterior spaces and directing rainwater from hard-to-reach areas to external drainage stations.
The accessible underground sections likely to be opened to the public include broad chambers beneath Hagia Sophia’s courtyard and adjoining corridors. Another notable area is a 4th-century tomb within the tunnel network, which visitors will be able to tour. In total, the tunnel system stretches over a kilometer, weaving beneath and around the monument like unseen veins, intricately connecting different spaces.
Visitor access will be carefully managed to preserve the delicate environment, with controlled entry likely through a reservation system to prevent overcrowding. Once open, these areas will offer a rare opportunity for people to appreciate the immense architectural and engineering complexity that supports and surrounds Hagia Sophia.
Similar subterranean networks exist elsewhere in Istanbul, many of which were built originally for water transmission and storage but have long been neglected. The enduring stability of Istanbul’s monumental structures owes much to these robust underground infrastructures. If Hagia Sophia’s restoration sets a precedent, many such projects could expand across the city, revealing and preserving Istanbul’s hidden heritage. Exposing these underground spaces will protect them and dispel myths and legends, allowing them to be understood and valued as tangible historical sites.
Diker stresses the importance of transforming these spaces from forgotten and neglected “waste dumps” into accessible cultural assets. While excavation was challenging in the past – leading to tunnels being filled with debris – modern techniques now allow relatively low-cost cleaning and preservation. The continued survival of these structures over centuries is a testament to their resilience and craftsmanship.
Ultimately, opening Hagia Sophia’s underground network to the public will add a remarkable dimension to cultural tourism, architectural history and archaeology. It invites visitors to experience firsthand the layered legacy beneath one of the world’s most iconic monuments, bringing the unseen to light and enriching Istanbul’s cultural narrative for generations to come.
Courtesy: Dailysabah
