Millions of Shia Muslims have gathered in the Iraqi city of Karbala to commemorate the death of Prophet Mohammed’s grandson who was killed there more than 1,300 years ago. The national holiday is known as the Ashura holiday.
The vast influx of people puts huge stress on infrastructure and services. Local companies and the government are investing heavily to try to improve the situation.
They are being helped by the country’s biggest foreign investor, Iran.
Al Jazeera's Charles Stratford reports.