Doric architecture was the earliest and the simplest of the classical Greek architectural forms. On account of this elegant simplicity and robust functionality, it is also the form of architecture you are most likely to see still standing in Greece today. Doric architecture was characterized by short, wide columns with no base and no fluting. The top of classical Greek columns is called the "capital"; Doric capitals were rounded, simple affairs compared to what would come later. The roofs of Doric buildings were usually shallowly sloped, leading up to a central ridge. Examples of such buildings include the celebrated Parthenon in Athens.
Architects of the Ionic style strived to produce longer, more slender columns, and it is these longer columns that can be found on buildings such as the Temple of Athena Nike in Athens. While the architects could not produce perfectly straight columns without compromising on structural integrity, they bypassed this by using a technique called "entasis." This entailed incorporating a slight, almost imperceptible, bulge into each section of the column, which gave the optical illusion of the column being straight. Ionic capitals were more ornate than their Doric counterparts and typically included pairs of spiraling carvings mimicking the horns of a ram.
The practice of using entasis to give the impression of a straight column was carried over into Corinthian architecture. This style of architecture was far more ornate, as represented by the Corinthian capital, which included carvings of flowers, leaves and scrolls of paper. The roofs of Corinthian buildings were generally flat, unlike the slanted roofs of Doric and Ionic buildings. An example of an original Corinthian building is the Temple of Sybil in Rome.
Such was the enduring appeal of Ancient Greek architecture that it caught the attention of retro-looking European and American architects in the 19th Century. These architects, scouring history for inspiration, began the Classical revival, which lasted from 1820 to 1860. Examples of this architecture include Le Madeleine in Paris, designed by Pierre-Alexandre Vignon, and Edward Crane’s Cobourg in Ontario. The Classical revival led to a mish-mash of styles, as 19th-Century architects, buoyed by the possibilities offered to them by improved technology and building practices, filled their designs with a mixture of Ionic, Doric and Corinthian influences.