A massive early-evening blaze destroyed Manhattan’s Serbian Cathedral of Saint Sava on Sunday, just hours after hundreds of people celebrated Orthodox Easter services in the 19th-century church in the Flatiron District. Onlookers and distraught parishioners watched in horror as the New York Fire Department responded with nearly 200 personnel to the four-alarm fire, which reportedly broke out just before 7 p.m. on the structure’s first floor. Flames shot out of towering stained-glass windows as the timber-frame roof was gutted. No injuries were reported. City officials said the cause of the fire would be investigated, but it did not appear to be suspcious.