A mysterious tunnel dug under the Church of St. Polyeuctus

The underground construction consisted of two large rooms connected by a tunnel, apparently related to the so-called prosthesis of the church: the room next to the altar where bread and wine were prepared according to the precepts of the Byzantine Church.

Parts of the underground chambers were decorated with mosaics and carved blocks of marble, according to archaeologists.

The Crusaders emptied the church

The underground spaces were first discovered during road construction in the 1960s, but were closed again when the area was built on.

The ruins sat empty for years and fell into disrepair, but last year the Istanbul municipality started a major project to turn the ruins into a tourist attraction.

The Church of St. Polyeuctus was built between 524 and 527 AD. Under Emperor Justinian, one of the most powerful emperors of the Byzantine Empire. It was the largest and largest church in Constantinople upon its completion, but Justinian never finished building it, and 10 years later the building surpassed the Hagia Sophia, now a mosque.

Only ruins remain today, but experts believe that the Basilica of Saint Polyeuctus was richly decorated and may have had an early dome, with a design that served as a prototype for the more famous Hagia Sophia.

However, the church was abandoned in the 11th century when it was badly damaged in an earthquake. Finally, the building was completely destroyed during the Fourth Crusade in 1204, when greedy crusaders attacked and sacked Constantinople instead of Jerusalem, their original target.

The Crusaders took various parts of the church home and placed them in their own churches, as far away as Barcelona and Vienna. The church’s two richly carved columns – known as Blasturi acritanis Or “Columns of Acre” – it is now part of St. Mark’s Basilica in Venice.

After the Ottomans occupied Constantinople in 1453, unexpected construction work was carried out on the ruins of the Church of St. Polyeuctus.

It is therefore remarkable that the underground spaces have held out for 1,500 years, and also because there have been many earthquakes in the area. According to archaeologists, this indicates that it was built to withstand earthquakes.

Istanbul has been hit by dozens of earthquakes over the past 1,500 years, but this structure has survived them all. “We must learn something from this,” said Maher Polat, deputy secretary-general of the Istanbul municipality.