Definition: In this task, you need to generate an appropriate title for the given summary of some paragraph. The generated title must be short and should include the main topic of the given text. Your summary should be less than 20 words long.
Input: The day of Ashura is marked by Muslims as a whole, but for Shia Muslims it is a major religious commemoration of the martyrdom at Karbala of Hussein, a grandson of the Prophet Muhammad.

What is Ashura?