• Orders: The use of architectural orders – Doric, Ionic, and Corinthian (later including Tuscan and Composite) – is a defining feature. Each order has specific characteristics for columns, entablatures (horizontal beams above columns), and pediments (triangular gables).
• Proportion and Harmony: Classical architecture emphasizes mathematical proportions and a sense of balance and harmony between different parts of a building.
• Symmetry: Buildings are often designed with a central axis, with elements on either side mirroring each other, creating a sense of order and formality.
• Geometric Forms: Simple geometric shapes like squares, rectangles, circles, and spheres are the basis of classical design.
• Emphasis on Decoration: Classical buildings often feature decorative elements like friezes (sculpted bands), moldings, and capitals (ornate tops of columns).

Materials and Techniques

• Stone: Marble, granite, and other types of stone were the primary materials used in classical architecture, due to their strength and durability.
• Post and Lintel System: Early Greek architecture employed a post and lintel system, where horizontal beams (lintels) rested on vertical supports (posts).
• Arches and Vaults: Romans adopted and perfected the use of arches and vaults, allowing for grander and more complex interior spaces.