I exported a CSV file from freebase.com that contained all the skyscraper fields I wanted to use. Then I created a simple shell script to import it from the CSV. Note that I only used a shell script for convenience, you could just as easily do this from a ProcessWire template file if you preferred it or needed to do this from Windows, etc.
Below is a simplified example of how to do this. The example is fictional and doesn't line up with the actual structure of the skyscrapers site, nor does i