The mosque was crowded at the time.
Mecca is preparing to host hundreds of thousands of people for the annual Hajj pilgrimage. In 2014, Saudi authorities began a major expansion of the site.
As such the area of the Grand Mosque will be increased by 400,000 square metres in order to accomodate 2.2 million people at a time.
Islam asks every follower who is capable to perform a pilgrimage to the site at least once in their life.
Over the years, several tragedies have occurred due to the sheer number of people making the trip.
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