The Ancient Greeks were well-known for their frescos, like this one of dolphins shown here. A fresco is a painting that is done on wet plaster so that the paint penetrates the plaster. Historians believe that this form of painting originated in Crete, a large island off the coast of Greece. The style of painting was well suited to the Greek islands, a place where heat, humidity, and sea air could easily deteriorate other styles of wall painting. This image of swimming dolphins is reflective of the warm ocean-side environment where this artistic technique emerged.