The continuous development of new ideas and technologies in engineering and architecture constantly reshapes design approaches in construction. However, the long-term use of certain structural elements provides designers with reliable reference points. In this context, castellated beams are steel structural members that have been widely used for many years and still maintain their significance today. This study comprehensively examines the historical development, manufacturing methods, areas of application, and structural advantages of castellated beams in light of the literature. Hexagonal and circular openings are among the most common manufacturing types, each offering distinct advantages in terms of production time, cost, and design flexibility. The literature emphasizes that castellated beams possess versatile benefits, such as enabling economical long-span solutions, compatibility with service systems, resistance to vibrations, and aesthetic contributions. Numerous studies have investigated the static and dynamic behavior of castellated beams using the finite element method. In the literature, castellated beams with different web opening geometries such as circular, square, pentagonal, hexagonal, diamond and octagonal have been analyzed and it has been shown that the geometry of the openings plays a decisive role in the displacement, stress distribution and vibration characteristics. Furthermore, studies in the literature have shown that structural reinforcements applied to web joint regions have been demonstrated to enhance the strength of beams. This study also details the manufacturing processes of castellated beams and compares the hexagonal and circular opening types. Additionally, their major applications in modern structures—such as parking facilities, industrial plants, office buildings, and energy structures—are presented with examples. In conclusion, castellated beams stand out as an innovative and efficient design solution in modern construction, offering significant advantages from both engineering and architectural perspectives.