Samuel Granados created two LEGO maps of the Americas, one one each side of a vertical surface, and used stacks of varying levels to indicate immigration patterns:
His project is very funny: a 3D cartogram about emigration and inmigration between american countries. But in true 3D: made with Lego pieces, as he explains, "to seize the space of the exhibition" and "allow you to watch teh cartogram from different perspectives".
One side of the map show the emigrants of each zone, the opposite shows the inmigrants (both represented by the volume of the pieces).
Link via Geekologie | Artist's Website | Photo by the artist