Almost three million people make the Islamic pilgrimage to Mecca each year. That makes this gathering in Saudi Arabia the world's largest.
With millions of pilgrims coming to perform the hajj every year, it's not hard to image how sophisticated the systems built to deal with them have become. The fact that an entire ministry in Saudi Arabia (the Ministry of the Hajj) is devoted to the event should indicate the logistical nightmare the hajj season brings. The ministry takes care of everything from shuttle bus transportation (equipped with GPS tracking) to campsite distribution for pilgrims to training a myriad of seasonal workers.
In the past, nearby Mina was especially known for dangerous stampedes. In 2006, almost 350 pilgrims were killed in one. Today, the area has been redesigned: Five floors, medical clinics, emergency exits and a helipad. A closed-circuit camera system monitors all movement in real time and if even a slight bottleneck looks to be forming (the source of previous fatal stampedes), traffic controllers move in. Saudi Arabia's telecom operator has installed over 1,000 cellphone towers to ensure cellphone coverage at all of Mecca's religious sites. At the Grand Mosque, pictured above along with the famous four-faced clock, the marble floor tiles have a temperature-regulated cooling system that pumps cold water through the pipes. The building also possesses one of the world's largest air-condition units, according the Saudi government. A rooftop view attracts many worshippers and in recent years escalators have been added alongside stairways on the northern and southern sides of the building.