
Watkins' vision of forts on wheels materialized in the form of military tanks, introduced at the beginning of the 20th century.
Tom Geoghegan. "Ten 100-year predictions that came true", BBC News Magazine. 11 Jan 2012. http://www.bbc.co.uk/news/magazine-16444966
http://www.bbc.co.uk/news/magazine-16444966