merlons

Merlons are the solid, raised sections of a crenellated parapet, the blocks that alternate with gaps called crenels or embrasures. They form the protective enclosure on top of a fortification wall and provide cover for defenders while allowing them to observe and fire upon attackers through the crenels.

Typically rectangular or polygonal, merlons can be evenly spaced or vary with the wall's profile. In different regions they may be tall, low, stepped, or rounded. The spacing, height, and shape influence the wall's defensive capability and its visual appearance. The gaps between merlons are crenels, while the openings through which defenders fire are called embrasures or loopholes.

Merlons were a standard feature of medieval European fortifications and castles from the 12th century onward, and they remained common in early modern military architecture. They appear in many Gothic and Renaissance forts and in some urban fortifications, reflecting the era's emphasis on controlled fields of fire and protected vantage points.

In contemporary architecture, merlons are often retained as decorative elements to convey a fortress-like aesthetic. They may also appear in restoration projects and on city walls that preserve crenellations for historical or stylistic reasons.