When this year’s Ramadan begins Thursday, workers will be rushing to get the lights ready for the unveiling of the Royal Mecca Clock Tower in the world’s most sacred city for Muslims. Muslim scholars say the clock will challenge Greenwich Mean Time, because Mecca, Saudi Arabia is the “true centre of the Earth.” Once completed, the clock’s 21,000 green and white lights will flash five times per day reminding local faithful to pray. It’s unclear whether bankers in Dubai will reset their watches, but a manager of the giant hotel and office complex where the clock is located says the goal is for Arabia Standard Time (three hours ahead of GMT) to overtake the standard time set by at London’s Big Ben for the past 125 years.