In their original Greek version, Doric columns stood on the porch of a temple without a base; their vertical shafts were fluted with parallel concave grooves; and they were topped by a smooth capital that flared from the column to meet a square abacus at the intersection with the horizontal beam ("entablature") that they carried. A pronounced feature of both Greek and Roman versions of the Doric order are the triglyphs and metopes. The triglyphs are decoratively grooved and represent the original wooden end-beams, which rest on the plain frieze that occupies the lower half of the entablature. Under each triglyph are peglike guttae that appear as if they were hammered in from below to stabilize the post-and-beam ("trabeated") construction. A triglyph is centered above every column, with another (or sometimes two) between columns. The spaces between the triglyphs are the metopes. They may be left plain, or they may be carved in low relief. Because the metopes are somewhat flexible in their proportions, the modular space between columns ("intercolumniation") can be adjusted by the architect.
Early examples of the Doric order include the temples at Paestum, in southern Italy, a region called Magna Graecia, which was settled by Greek colonists and retained a strongly Hellenic culture.
The Temple of the Delians (illustration right) is a "peripteral" Doric temple, the largest of three dedicated to Apollo on the island of Delos. It was begun in 478 BCE and never completely finished. During their period of independence from Athens, the Delians reassigned the temple to the island of Poros. It is "hexastyle", with six columns across the pedimented end and thirteen along each long face. All the columns are centered under a triglyph in the frieze, except for the corner columns. The plain, unfluted shafts on the columns stand directly on the platform (the stylobate), without bases. The recessed "necking" at the top of the shafts and the wide cushionlike echinus are a slightly self-conscious archaizing features, for Delos is Apollo's ancient birthplace.
A classic statement of the Greek Doric order is the Temple of Hephaestus in Athens, built about 449 BCE. See the Wikipedia entry for photographs that show its details. The contemporary Parthenon, the largest temple in classical Athens, is also in the Doric order, although it has some Ionic elements.
In the Roman Doric version, the columns were slightly less robust in their proportions. Below their caps, an astragal encircled the column like a ring. They had moldings at their bases and stood on low square pads. Roman Doric columns often stood on plinths. In the Roman Doric mode, columns were not invariably fluted.
The Doric order was one of the 
The Temple of the Delians (illustration right) is a "peripteral"