In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Q: (CNN) -- Each year, more than 3 million Muslims commit to Hajj, the pilgrimage to Mecca that represents the fifth and final "pillar" of Islam and the largest annual human gathering on the planet. Every Muslim who is physically and financially able to do so is expected to make this pilgrimage once in their lifetime. As described in the Hadith of Gabriel, each pillar of Islam acts as a guide to day-to-day conduct for Muslims, outlining proper professions to God, prayer and spiritual mindfulness, not unlike the Book of Common Prayer for Anglicans or Judaism's Siddur. For this year's Hajj, iReporters from around the world documented their journeys, describing their experiences as they complete this Islamic sacrament. Thanks to the power of social media and platforms like CNN's iReport, they've been able to share their faith with the world, giving Muslims and non-Muslims alike a glimpse of the significance of this powerful and transformative event.More young Muslims embarking on Islamic pilgrimage than ever before2011 Hajj could be a flashpoint for global Islamic revivalPilgrimage is a defining moment in the life of MuslimsFollow iReporters as they complete their Hajj 
 Question:"In reality, many of these people, when not in _, will fight and spill each other's blood.
A: 
Mecca