Ismail Fakirullah Tomb & Light Refraction Mechanism Located in Aydinlar (Tillo) District of Siirt, Ismail Fakirullah Tomb is one of the three structures connected to the Light Refraction Mechanism. The tomb was built by Ibrahim Hakkı, one of Ismail Fakirullah's students, in the 18th century following Ismail Fakirullah's death. Although the tombstones date back to the 1800s, some of its authenticity has been lost due to incorrect restoration efforts in 1963. Ismail Fakirullah Tomb consists of two rooms and a hallway with one large and two small domes, as well as a tower. Its square design is covered by a dome that is supported by squinches. The building features two-level windows on all its facades. The lower-level windows have a straight lintel with a curved arch window pediment, while the higher-level windows have a pointed arch span. The entrance of the tomb is a square room covered by a dome that leads to the main section, which is also square in shape. The interior of the tomb has no decorations and contains other tombs besides Ismail Fakirullah's. In close proximity is an octagonal tower with a height of 10 meters. The tomb, tower, and light refraction mechanism are all connected to the Kalet'ul Üstad, a wall made of rubble and undressed stones without any binding substance. This wall is located on a hill overlooking the Botan Valley about 3-4 kilometers east of Tillo and is considered significant. Every year on 21st March (Nevruz – inscribed in 2009 on the Representative List of the Intangible Cultural Heritage of Humanity) and 23rd September, the first light of the rising sun is reflected to the reflector precisely embedded in Ismail Fakirullah's tower, and from a mechanism in his tower, highlights the grave of Ismail Fakirullah. The lightning starting from the lower left part of the grave continues for approx. 6 mins. In the first 3 mins., the grave is completely highlighted from the light reflected through the tower and in the remaining 3 mins. the light fades away in the opposite direction from the upper part of the grave. The Ismail Fakirullah tomb and its light refraction mechanism are a testament to a long-standing spiritual and cultural heritage that has endured for many centuries. The Sufi belief is transmitted through this mechanism, which emphasizes the grave of Ismail Fakirullah on the 21st of March, which is thought to be the start of a new year among several people and communities in the region. Ismail Fakirullah Tomb & Its' Light Refraction Mechanism has been listed in the Tentative List of UNESCO in 2015.