Comment.

A response to a study on whether terrorism is a force for urban dispersal or whether terrorism drives people together is presented. It cites the costly travel effect and the city walls effect which counter the tall targets effect. The author says that terrorism is in decline in Europe and North America, but is on the rise in the Middle East. The incidence of terrorism in large cities in the U.S. and Great Britain which is indicative of the tall targets effect is mentioned. The article elaborates on the correlation between terrorism and urban land use.