Evolo

Wait: you haven't heard of Evolo, and your on this site??  You can't even BEGIN to talk about skyscrapers, without considering this highly integral magazine, and its corresponding competition.  It has been the defining skyscraper competition/discussion of our time, comparable to The Chicago Tribune Tower competition of 1922.  With luck, more info will come from it.

To remedy that concern from anyone who hasn't seen the site, see: here and here. 

  Diagram of Evolo Winners, 2006-2011

 As for some past research:

The above diagram highlights some of the findings of past Evolo winners.  Each of the honorable mentions and top prize winners since the competitions inception were charted, showing that New York, Paris, and Hong Kong were primary favorites of jurors and submittees alike.  New York in particular had almost double the entries of other site locations.  Europe and Southeast Asia were very well represented overall.

Though this is a guide by which to consider prospective sites, it is by no means a final guarantee of top billing for locations.  Most sites selected related heavily to the design proposals, and are used to underline the overall message.  

SHARE