unveil : 公佈於眾

CHICAGO -- Visitors to the Sears Tower's new glass balconies all seem to agree: The first step is the hardest.

"It's like walking on ice," said Margaret Kemp, of Bishop, California, who said her heart was still pounding

even after stepping away from the balcony. "That first step you take -- 'am I going down?"'

Kemp was among the visitors who got a sneak preview of the balconies Wednesday.

"The Ledge," as the balconies have been nicknamed, open to the public Thursday.

sneak preview : 未公諸於眾之前預演 Ledge : 岩壁上突出的狹長部分 nickname : 起綽號

The balconies are suspended 412 metres in the air and jut out 1.22 metres from the building's 103rd floor Skydeck.

They're actually more like boxes than balconies, with transparent walls, floor and ceiling.

jut out : 突出;伸出 Skydeck : 露天展望台

Visitors are treated to unobstructed views of Chicago from the building's west side and

a heart-stopping vista of the street and Chicago River below -- for those brave enough to look straight down.

unobstructed : 不被擋住視線的 heart-stopping : 驚心動魄的 vista : 遠景

John Huston, one of the property owners of the Sears Tower, even admitted to getting "a little queasy" the first time he ventured out.

But 30 or 40 trips later, he's got the hang of it.

venture : 帶有風險, 冒險 queasy : 想吐的;反胃的 get the hang of something : 通過練習找到竅門

"The Sears Tower has always been about superlatives -- tallest, largest, most iconic," he said.

"Today is also about superlatives. Today, we present you with 'the Ledge,' the world's most awesome view,

the world's most precipitous view, the view with the most wow in the world."

superlative : 最高的;最好的 iconic : 最具典型性的 awesome : 令人讚嘆的, 很好的 precipitous : 險峻陡峭的 wow : 哇!(表示驚訝的叫聲)

The balconies can hold five tons, and the glass is 3.8 centimetres thick, officials said.

Sears Tower officials have said the inspiration for the balconies came from the hundreds of forehead prints

visitors left behind on Skydeck windows every week. Now, staff will have a new glass surface to clean: floors.

The balconies are just one of the big changes coming to the Sears Tower. The building's name will change to Willis Tower later this summer.

Last week, officials announced a 5-year, $350 million green renovation complete with wind turbines, roof gardens and solar panels.