The world's largest clock began keeping time in Mecca on August 11, the start of Ramadan.

The Holy Mecca Clock is the most distinctive feature of the King Abdulaziz Endowment seven-building hotel complex, a project of the Saudi Binladen Group. The clock tower alone is estimated to have cost $3 billion to build.

The clock overlooks the Grand Holy Mosque and is set 400 metres high in one of the towers, which will be the second highest skyscraper in the world upon completion in three months' time. The clock has four faces, each measuring 43 metres in diameter.

On the order of the Saudi King, the clock was started one minute after midnight to mark the beginning of the Muslim month of fasting.