Getting the flow of thousands of pilgrims past the pillars smoothly is perhaps the biggest logistical challenge. A two-layered bridge has been built, with the pillars poking through walled holes in the top level, so pilgrims can cast their pebbles above and below simultaneously. Still, it's in the confines of this relatively narrow area that one person stumbling causes a chain reaction. Researchers are looking to limit the pace and flow of pilgrims heading to the pillars, to avoid crowds building up. They'll watch carefully this year to see if that works.
Innovations appear year after year.
Pilgrims have to cut a piece of hair on completing their Hajj. Men often shave their heads clean. Now large barber shop areas have been set up on ventilation grates, with air vents immediately sucking down any hair shaved off the pilgrims' heads. This should improve hygiene considerably. Fireproof tents at Mina with sprinklers and air-conditioning bring comfort and safety, along with water mist sprayers in the desert at Arafat.