This lecture examines the Bauhaus building at Dessau (1925–26) designed by Walter Gropius and explains how it became a landmark of 20th-century modern architecture. The design reflects core Bauhaus principles of functionalism, logical zoning of activities, open floor plans, flat roofs, white cuboidal forms, absence of ornamentation, and extensive use of glass and steel. The workshop wing with its glass curtain wall stands out as a pioneering example of modern construction and abundant natural light. The lecture also highlights Bauhaus interiors, functional furniture such as Marcel Breuer’s tubular steel chair, and the Masters’ Houses at Dessau. It further connects Bauhaus functional planning to Alvar Aalto’s Paimio Sanatorium, showing how zoning, sunlight, ventilation, and furniture design were carefully integrated to serve human needs. The session concludes by demonstrating the lasting influence of Bauhaus ideas on later modern and high-tech architecture.