Tourists watch a model of the world's tallest tower, Buj Khalifa at the entrance of observation deck after it has been unexpectedly shut down in Dubai, United Arab Emirates, Monday, Feb. 8, 2010. The closure is potentially disappointing thousands of tourists and marring the spire's image just a month after it opened. The precise cause of the $1.5 billion Dubai skyscraper's closure remained unclear. In a brief statement responding to questions, building owner Emaar Properties blamed the closure on "unexpected high traffic," but then suggested that electrical problems were also at fault. (AP Photo/Kamran Jebreili)