Layering images for conceptual effect

This is an image inspired by all that has been going on in Europe lately. It is a composite of five separate files. One is of the pensive man, another of a glass globe I shot recently, another is of a computer screen with trading data on it, one is a hazy shot of a city, and the final one is of smoke to add atmosphere. The whole assemblage was mixed by varying the layer type in Photoshop.