held and Burj Khalifa is opened. Burj Dubai was renamed Burj Khalifa in honour of the President of the UAE and ruler of Abu Dhabi, Sheikh Khalifa bin Zayed al Nahyan. 10 March 2010: Council on Tall Buildings and Urban Habitat certifies Burj Khalifa as world's tallest building. Real estate values In March 2009, Mohamed Ali Alabbar, chairman of the project's developer, Emaar Properties, said office space pricing at Burj Khalifa reached US$4,000 per sq ft (over US$43,000 per m2) and the Armani Residences, also in Burj Khalifa, sold for US$3,500 per sq ft (over US$37,500 per m2). He estimated the total cost for the project to be about US$1.5 billion. The project's completion coincided with the financial crisis of 2007–2008, and with vast overbuilding in the country, leading to high vacancies and foreclosures. With Dubai mired in debt from its huge ambitions, the government was forced to seek multibillion-dollar bailouts from its oil-rich neighbor Abu Dhabi. Subsequently, in a surprise move at its opening ceremony, the tower was renamed Burj Khalifa, said to honour the UAE President Khalifa bin Zayed Al Nahyan for his crucial support. Because of the slumping demand in Dubai's property market, the rents in the Burj Khalifa plummeted 40% some ten months after its opening. Out of 900 apartments in the tower, 825 were still empty at that time. However, over the next two and a half years, overseas investors steadily began to purchase the available apartments and office space. By October 2012, Emaar reported that around 80% of the apartments were occupied. Official launch ceremony The ceremony was broadcast live on a giant screen on Burj Park Island and on smaller screens elsewhere. Hundreds of media outlets from around the world reported live from the scene. In addition to the media presence, 6,000 guests were expected. The opening was held on 4 January 2010. The ceremony featured a display of 10,000 fireworks, light beams projected on and around the tower, and further sound, light and water effects. The celebratory lighting was designed by UK lighting designers Speirs and Major Associates. Using the 868 powerful stroboscope lights that are integrated into the façade and spire of the tower, different lighting sequences were choreographed, together with more than 50 different combinations of other effects. Controversies Fatalities Within 17 months of the building's official opening, a man described as "an Asian in his mid-30s", who worked at