The roots of this publication lie in a lecture that Illkka Vähäaho gave in 2009 at the World Tunnel Congress in Budapest, Hungary.

Following this, the theme has kept him lecturing around the world, mostly in the Far East.

Using the City of Helsinki, a forerunner in the field, as a prime example, he has written several papers, given numerous interviews, completed many questionnaires and helped to arrange a number of site visits in order to give inspiration and encouragement to other cities and decision makers on the possibilities of Underground Space Use…