The aim of the publication was to bring information about violations of building Byzantine Hagia Sophia in Istanbul. Hagia Sophia is the most important Byzantine church built in the 6th century, which became a model for all the former architecture. Until now it is one of the largest churches in the world. He became an inspiration and role model for all generations of builders and architects. The study provides information about the violation of the building and its causes. It also describes the remediation, which were made in its history. The issue of building violations is mainly due to plate tectonics activity in the territory of Turkey. This caused a series of damage to individual parts of the building. Unsuitable construction solutions, the issue of external influences in the vicinity of the structure but also the influence of religion throughout history has completely changed the concept of the building, especially the exterior. © 2016 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the organizing committee of WMCAUS 2016.