People from all walks of life observe Qadr night (the 23rd of the fasting month of Ramadan) in Imamzadeh Saleh in Tehran, on April 13.

The Holy Quran was revealed to Prophet Mohammad (PBUH) on Qadr nights, which is observed on the 19th, 21st and the 23rd of Ramadan. The occasion also marks the martyrdom of Imam Ali (AS), the first Shia Imam.