Sky lobby
Building Name Year Location Floors of sky lobby ( s )
875 North Michigan Avenue 1969 Chicago , Illinois , United States 44
30 Hudson Yards 2019 New York City , New York , United States 35
One World Trade Center 1972 New York City , New York , United States 44 , 78
Two World Trade Center 1973 New York City , New York , United States 44 , 78
Willis Tower 1973 Chicago , Illinois , United States 33/34 , 66/67
NatWest Tower 1980 London , United Kingdom 23/24
JPMorgan Chase Tower ( Houston ) 1982 Houston , Texas , United States 60
Wells Fargo Plaza ( Houston ) 1983 Houston , Texas , United States 34/35 , 58/59
Williams Tower 1983 Houston , Texas , United States 51
Columbia Center 1985 Seattle , Washington , United States 40
Miami Tower 1987 Miami , Florida , United States 11
Seattle Municipal Tower 1990 Seattle , Washington , United States 40
Petronas Twin Towers 1999 Kuala Lumpur , Malaysia 41/42
Izumi Garden Tower 2002 Tokyo , Japan -
First World Hotel 2008 Genting Highlands , Pahang , Malaysia 3 , 8
Taipei 101 2004 Taipei , Taiwan 35/36 , 59/60
Shin Kong Life Tower 1993 Taipei , Taiwan 16
Revenue Tower 1990 Wan Chai North , Hong Kong -
Immigration Tower 1990 Wan Chai North , Hong Kong -
Central Plaza 1992 Wan Chai North , Hong Kong -
Buildings with sky lobbies
The former World Trade Center , designed by Minoru Yamasaki , used sky lobbies , located on the 44th and 78th floors of each tower . View from the sky lobby in the JPMorgan Chase Tower , Houston The Nina Tower sky lobby
A sky lobby is an intermediate interchange floor in a skyscraper where people can change from an express elevator that stops only at the sky lobby to a local elevator which stops at every floor within a segment of the building. When designing very tall (supertall) buildings, supplying enough elevators is a problem - travellers wanting to reach a specific higher floor may conceivably have to stop at a very large number of other floors on the way up to let other passengers off and on. This increases travel time, and indirectly requires many more elevator shafts to still allow acceptable travel times - thus reducing effective floor space on each floor for all levels. The other main technique to increase usage without adding more elevator shafts is double-deck elevators. Early uses of the sky lobby include the original Twin Towers of the World Trade Center and 875 North Michigan Avenue in Chicago.