Simplify the following text for a Grade 8 native English-speaking person.
Original: Burj Khalifa ( `` Khalifa Tower '' ) , known as Burj Dubai prior to its inauguration , is a skyscraper in Dubai , United Arab Emirates , and is currently the tallest man-made structure ever built , at 828 m. Construction began on 21 September 2004 , with the exterior of the structure completed on 1 October 2009 .
Simplified: Burj Khalifa or `` Khalifa Tower '' is a very tall ( 160 stories high ) skyscraper in Dubai , United Arab Emirates . Before the building opened it was called Burj Dubai .