Sirkeci Church
The remains of an unknown Byzantine church were uncovered during construction work in Sirkeci in 2000. The structure had a triple apse and recessed brickwork, suggesting it dates to the Middle Byzantine period (perhaps from the 11th or 12th century). The structure continued west of the apses nearly 20 meters, but it was destroyed by bulldozers during the construction. The restored remains are now located in the lowest floor of Halil Lütfü Dördüncü İş Merkezi on Ankara Street.

Based on plan by Özgümüş
Sources
“A Byzantine church at Sirkeci in Istanbul” by Ferudun Özgümüş
Architecture and Ritual in the Churches of Constantinople: Ninth to Fifteenth Centuries by Vasileios Marinis
Resource
Byzantine Churches of Constantinople (Byzantine Legacy Flickr)