A pigeon's feather among pockmarks on a marble floor in the Data Darbar shrine in Lahore, Pakistan, on Friday, the day after two suicide bombers killed 42 people and wounded around 180. Thousands of Sufi Muslims gathered in the shrine, arguably the country's most important, when the attacks occurred. Recently, Islamic militants have been targeting sects of Islam that they consider heretical. Sufism is a moderate strand of the religion that's more than 1,000 years old.