I saw these in person a little while ago and they are amazing: they are huge and the level of detail is just ridiculous:

After researching his chosen city, Nishino spends up to two months walking and photographing the urban environment, capturing thousands of images of streets, alleys, corners, and vistas from every imaginable angle. He then prints his contact sheets, cuts out the individual frames, and affixes them by hand onto board, in the process creating a large-scale, collaged map that expresses a truly personal interpretation of the featured location. Once the collages are complete, Nishino digitally photographs and presents them as high resolution, large-scale prints, often as big as 6 x 7 feet.