Cleaners , 206-storey tall Burj Khalifa , Dubai . 清潔工， 206層樓高的杜拜塔，杜拜。

Don't look down! Window cleaners tackle the world's tallest skyscraper | Mail Online http://www.dailymail.co.uk/news/article-2155934/Dont-look-Window-cleaners-tackle-worlds-tallest-skyscraper.html