This city was formerly home to a cemetery called “the field of thorny trees.” One text states that this city will have seven gates, each guarded by two angels, to prevent entry of the Dajjal. A document named for this city says that each of nine tribes was responsible for its own blood money and ransom payments. A building in this city was the first of its kind to have two niches. Another building in this city has a Green Dome on its southeast corner above several graves. This city is called by its original name of Yathrib (-5[1])in a text (-5[1])discussing (10[1])the Battle of the Trench, (10[1])which took place just outside (-5[1])it. The beginning of the Islamic calendar is marked (10[1])by a pilgrimage to this city called the Hijrah. (10[2]-5[1])For 10 points, (10[1])Muhammad and his followers fled to what second-holiest city in Islam after Mecca? ■END■ (10[2])