If you're scared of heights, it may be time to look away now.
Not content with having the tallest building in America, the owners of Sears Tower in Chicago have installed four glass box viewing platforms which stick out of the building 103 floors up.
The balconies are suspended 1,353 feet in the air and jut out four feet from the building's Skydeck.
Fearless: Anna Kane, five, spreads out on the floor of the 10ft square box which is 1,353ft up
Spectacular: She also enjoyed amazing views out across the city
'At first I was kind of afraid but I got used to it', 10-year-old Adam Kane from Alton, Illinois, said as clouds drifted by below.
'Look at all those tiny things that are usually huge.' John Huston, one of the owners of the Sears Tower, even admitted to getting 'a little queasy' the first time he ventured out on to the balcony. However, after 30 or 40 trips, he seems to have got used to it.
Thrillseekers: The boxes jut out four feet from the building and were specifically designed to make visitors feel as if they are floating
'The Sears Tower has always been about superlatives - tallest, largest, most iconic,' he said.
'The Ledge is the world's most awesome view, the world's most precipitous view, the view with the most wow in the world.'
The balconies are 10ft high and 10ft wide, can hold five tons, and have glass which is 1.5 inch thick
Unfazed: Although some adults felt dizzy after experiencing the Ledge, children seemed to take it in their stride