Death of Houshang Seyhoun (Iranian architect and artist) on May 26 marks the passing of one of Iran’s most influential modern architects and artists. Seyhoun died at the age of 93 in Vancouver, Canada, on this date in 2014. Born in 1920 in Tehran, he left a lasting legacy in Iranian architecture and art. Seyhoun began his studies at the Faculty of Fine Arts at the University of Tehran and continued at the École des Beaux-Arts in Paris. After returning to Iran, he served as a professor and later as the dean of the Faculty of Fine Arts, playing a significant role in educating a new generation of Iranian architects. His most notable works include the design of the mausoleums of Avicenna in Hamedan, Omar Khayyam in Nishapur, and Kamal-ol-Molk. The mausoleum of Nader Shah in Mashhad is also among his prominent architectural achievements. Seyhoun’s death on May 26, 2014, was widely covered in Iranian and international media, with many artists, architects, and cultural figures commemorating his memory. Memorial ceremonies were held in various cities, and his works continue to be studied by researchers and students of architecture. This date is noted in some calendars as a reminder of Seyhoun’s impact on contemporary Iranian architecture and art. This observance was included in the 2014 calendar to recognize the importance of Seyhoun’s position and the influence of his works on the identity of modern Iranian architecture.