The Israa and Miraj refer to, two parts of an miraculous journey that Prophet Muhammad took in one night from Makka to Jerusalem and then an ascension to the heavens.
Israa is an Arabic word referring to Prophet Muhammad's miraculous night journey from Makka to Jerusalem - specifically, to the site of al-Aqsa Mosque in Jerusalem - as referred to in Surah Al-Israa in the Quran.
It is believed to have been followed by the Mi'raj, his ascension to heaven. According to some of the Hadith scholars this journey is believed to have taken place just over a year before Prophet Muhammad migrated to from Makka to Madina, on the 27th of Rajab.
Muslims celebrate this night by offering optional prayers during this night, and in many Muslim countries, by illuminating cities with electric lights and candles.