Jeddah Tower, soon to be the world's tallest building, is rapidly rising into the Saudi Arabian sky as construction steams ahead. And now its developers have announced they expect it to be ...

The 127-story Shanghai Tower is now the tallest building in China and the second tallest in the world. From breaking ground to completion, the building took almost seven years to complete.

The tower has long been touted as the next Burj Khalifa - the world's current tallest building. But the tower has been beset by problems, with work grinding to a halt when it was only a third built.

The drop tower is not a replacement for AtmosFEAR ... Mike Houck, director of Urban Green Spaces Institute, says a structure that tall and bright poses a threat to birds and other wildlife.