The Kharaghan Twin Towers are mausoleums that according to their remaining inscriptions were built in 1093 CE and 1067 CE. Located on the plains near Ghazvin, they house the tombs of two Seljuki era princes, Abu Saeed Bijar son of Sad and Abu Mansoor Iltai son of Takin and are built over the two burial sites 90 feet apart. The inscriptions on the towers identify the architects as Muhammad ibn Makki al-Zanjani and Abul-Ma'ali ibn Makki al-Zanjani in the later tower, who is probably the former's son or brother.The brick structures stand 15 meters tall and 4 meters wide, and make extensive use of geometry. Inside the older mausoleum there is a lamp and paintings. The both have a non-conic two-layered dome; the exterior domes have not survived. Both towers have octagonal chambers with engaged pilasters at every corner. Each of the eight facades of the two towers is adorned with a decorative panel.Each tower is made of thick brick walls onto which the decorative brick panels have been attached.The east tower has a north-east facing entrance while the West tower's entrance is to the north. Two of the buttresses at the eastern tower contain spiraling staircases within them. This is different at the Western tower where only one buttresses contains a staircase.