ワン・ワールド・トレード・センターの展望台が完成　地上400メートル、透けるガラスの上に立ったら...（画像）

A view through the Sky Portal shows a live video view of the streets below from One World Observatory, Wednesday, May 20, 2015, in New York. Visitors can stand on a round video platform that shows an actual livestream of the view straight down. The observatory atop the 104-story One World Trade Center opens to the public on May 29. (AP Photo/Mark Lennihan)

The World Trade Center Transportation Hub, left, and 3 World Trade Center are under construction in this view from One World Observatory, Wednesday, May 20, 2015 in New York. (AP Photo/Mark Lennihan)

A visitor to One World Observatory looks over Manhattan, Wednesday, May 20, 2015, in New York. The observatory atop the 104-story One World Trade Center opens to the public on May 29. (AP Photo/Mark Lennihan)

One World Observatory has a view of midtown Manhattan, including the Empire State Building, left, and 432 Park Ave., center, Wednesday, May 20, 2015 in New York. (AP Photo/Mark Lennihan)

Midtown Manhattan, including the Empire State Building, center, are seen from the observatory at One World Trade Center, Wednesday, May 20, 2015, in New York. The observatory atop the 104-story skyscraper opens to the public on May 29. (AP Photo/Mark Lennihan)

The Financial District and the World Trade Center, lower center, are seen from the observatory at One World Trade Center, Wednesday, May 20, 2015, in New York. The observatory atop the 104-story skyscraper opens to the public on May 29. (AP Photo/Mark Lennihan)

The Jersey City skyline is seen in this view from the observatory at One World Trade Center, Wednesday, May 20, 2015, in New York. The observatory atop the 104-story skyscraper opens to the public on May 29. (AP Photo/Mark Lennihan)

Eric Robinson, center, demonstrates City Pulse at One World Observatory, Wednesday, May 20, 2015, in New York. The interactive ring of high-definition monitors allows guests to view landmarks and neighborhoods that they view from above. The observatory atop the 104-story One World Trade Center opens to the public on May 29. (AP Photo/Mark Lennihan)

New York\'s Financial District, foreground, the Brooklyn Bridge and East River, center, and in the distance Brooklyn are seen from the observatory at One World Trade Center, Wednesday, May 20, 2015. The observatory atop the 104-story skyscraper opens to the public on May 29. (AP Photo/Mark Lennihan)

A view of New York is seen from One World Observatory during a media tour and preview in New York on May 20, 2015. This early visit to the Observatory at One World Trade Center will showcase all of the main attractions that the Observatory offers on floors 100 to 102 -- Voices, Foundations, Sky Portal, City Pulse and more. One World Observatory announced that its official public opening date will be May 29, 2015. AFP PHOTO / TIMOTHY A. CLARY (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)

In this Sunday, Sept. 7, 2014 photo, 1 World Trade Center towers above the lower Manhattan skyline in New York. The One World Trade observatory is expected to open in late spring 2015. (AP Photo/Mark Lennihan, File)

A view of Manhattan is seen from the One World Observatory May 20, 2015 during a media tour and preview in New York. This early visit to the Observatory at One World Trade Center will showcase all of the main attractions that the Observatory offers on floors 100 to 102 -- Voices, Foundations, Sky Portal, City Pulse and more. One World Observatory announced that its official public opening date will be May 29, 2015. AFP PHOTO / TIMOTHY A. CLARY (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)

A view of Manhattan is seen from the One World Observatory May 20, 2015 during a media tour and preview in New York. This early visit to the Observatory at One World Trade Center will showcase all of the main attractions that the Observatory offers on floors 100 to 102 -- Voices, Foundations, Sky Portal, City Pulse and more. One World Observatory announced that its official public opening date will be May 29, 2015. AFP PHOTO / TIMOTHY A. CLARY (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)

A time-lapsed view of New York seen through the years is viewed from the Sky Pod Elevator at the One World Observatory May 20, 2015 during a media tour and preview in New York. This early visit to the Observatory at One World Trade Center will showcase all of the main attractions that the Observatory offers on floors 100 to 102 -- Voices, Foundations, Sky Portal, City Pulse and more. One World Observatory announced that its official public opening date will be May 29, 2015. AFP PHOTO / TIMOTHY A. CLARY (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)

A time-lapsed view of New York seen through the years is viewed from the Sky Pod Elevator at the One World Observatory May 20, 2015 during a media tour and preview in New York. This early visit to the Observatory at One World Trade Center will showcase all of the main attractions that the Observatory offers on floors 100 to 102 -- Voices, Foundations, Sky Portal, City Pulse and more. One World Observatory announced that its official public opening date will be May 29, 2015. AFP PHOTO / TIMOTHY A. CLARY (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)

A time-lapsed view of New York seen through the years is viewed from the Sky Pod Elevator at the One World Observatory May 20, 2015 during a media tour and preview in New York. This early visit to the Observatory at One World Trade Center will showcase all of the main attractions that the Observatory offers on floors 100 to 102 -- Voices, Foundations, Sky Portal, City Pulse and more. One World Observatory announced that its official public opening date will be May 29, 2015. AFP PHOTO / TIMOTHY A. CLARY (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)