Mosaic depicting the wonders Nile river from a Roman bath. Egypt, and Nilotic landscape, became very fashionable among the upper classes in the first century AD. In this mosaic the artist tried to reproduce hippopotamus and crocodiles. Roman mosaics are constructed from geometrical blocks called tesserae, placed together to create the shapes of figures, motifs and patterns. Materials for tesserae were obtained from local sources of natural stone, with the additions of cut brick, tile and pottery creating colored shades of, predominantly, blue, black, red, white and yellow. Polychrome patterns were most common, but monochrome examples are known. Mosaic on display at the National Museum in Rome.