Egyptian vendors walk past Al-Hussein mosque as they prepare to celebrate Moulid al-Hussein, a Sufi gathering which commemorates the birth of the Muslim Prophet Muhammad's grandson, in Cairo, Egypt, Tuesday, Feb. 9, 2016 (AP)

A temporary tent is set up for celebrating Moulid al-Hussein, a Sufi gathering which commemorates the birth of the Muslim Prophet Muhammad's grandson, in Cairo, Egypt, Tuesday, Feb. 9, 2016 (AP)

An Egyptian vendor hangs Muslim prayer beads near al-Hussein mosque as preparations begin for celebrating Moulid al-Hussein, a Sufi gathering which commemorates the birth of the Muslim Prophet Muhammad's grandson, in Cairo, Egypt, Tuesday, Feb. 9, 2016 (AP)

Smoke from incense rises from a street stall as preparations begin for celebrations marking Moulid al-Hussein, a Sufi gathering which commemorates the birth of the Muslim Prophet Muhammad's grandson, in Cairo, Egypt, Tuesday, Feb. 9, 2016 (AP)