Yorkshire firm in sound barrier project to aid Mecca Muslims
The holy city of Mecca in Saudi Arabia is revered by Muslims as the birthplace of the prophet Muhammad.
About 13 million people visit Mecca annually, including three million for the annual hajj pilgrimage. The hajj is obligatory for able-bodied Muslims at least once in their lives. The focal point of Mecca is the giant mosque, Masjid al-Haram. This surrounds the Kaaba, a cube-shaped building.