This essay provides a comprehensive comparison between Moderne (Streamline Modern or Art Moderne) and Modern architecture styles, tracing their origins, characteristics, advantages, and disadvantages. Moderne architecture, emerging in the 1930s, is characterized by flattened roofs, horizontal lines, rounded edges, and subdued colors, often resembling nautical elements with minimal ornamentation, making it cost-effective and suitable for public spaces. However, it requires large spaces and lacks ornamentation, which may not appeal to everyone. Modern architecture, on the other hand, arose from technological advancements in steel, reinforced concrete, and glass, enabling the construction of taller, stronger, and more versatile buildings with efficient land utilization and greater design flexibility. While modern architecture allows for ornamented buildings and mixed colors, it is more expensive, requires specialized expertise, and can lead to the erosion of traditional designs. The essay also discusses the presence of both styles in Australia, using the Minerva Theatre and the Parliament House in Adelaide as examples, highlighting the evolution of cultural trends and architectural diversity.