Heaven is a place with in, the portal to it is also with in. The word mehrab comes from the word Harb which means to Fight, mehrab is the niche that is built in mosques where the imam stands to lead the prayer. the prayer is seen as a jihad or fight against the inner demons that distract us and take us away from the presence of the heart. When still, in state of presence one can experience heaven with in, united with the Beloved, returning home.