In classical architecture

Classical architecture

Classical architecture is a mode of architecture employing vocabulary derived in part from the Greek and Roman architecture of classical antiquity, enriched by classicizing architectural practice in Europe since the Renaissance...

, a sima is the upturned edge of a roof which acts as a gutter

Rain gutter

A rain gutter is a narrow channel, or trough, forming the component of a roof system which collects and diverts rainwater shed by the roof....

. Sima comes from the Greek simos, meaning bent upwards.

Form

The sima runs around all four sides of a building, the raking sima is continuous, while the simas on the other sides is broken by spouts. Early sima featured tubular or half cylindrical spouts, but these were mostly replaced with animal head spouts by the middle of the 6th century BC.

Simas may be made of terracotta or stone.

Decoration

Simas were normally decorated. Stone simas had continuous naratives, especially on the raking sides where they would not be interrupted by spouts, similar to a frieze

Frieze

thumb|267px|Frieze of the [[Tower of the Winds]], AthensIn architecture the frieze is the wide central section part of an entablature and may be plain in the Ionic or Doric order, or decorated with bas-reliefs. Even when neither columns nor pilasters are expressed, on an astylar wall it lies upon...

. Terracotta simas had repeating patterns that were easy to reproduce with molds.