Mecca's Abraj al-Bait Towers aren't so much towers as they are a multibuilding skyscraper complex that includes a hotel, residential apartments and a shopping mall. The architectural monstrosity isn't finished yet, but when it's completed, it will be the largest building in Saudi Arabia and it will boast the tallest clock tower in the world. The $3 billion complex is located directly across from the al-Haram Mosque, which houses Islam's most sacred site: the black, cubelike Kaaba. Abraj al-Bait's four-sided clock similar in design to the Westminster Clock in London is reportedly visible for more than 15 miles (25 km). Construction on the entire project was originally due to be completed in 2009, but the towers endured several setbacks (including two fires) and are now scheduled to be finished in 2011. The clock has been up and running since August 2010.