Art Nouveau is an ornamental art and design style characterized by flowing, organic forms inspired by nature. It often features curving lines, floral motifs, vines, and asymmetry, blending fine craftsmanship with artistic detail. Common materials include glass, wrought iron, and ceramics, with famous examples found in architecture, furniture, and illustration. Notable artists include Alphonse Mucha and Antoni Gaudí.

Art Deco is a sleek, modern design style that emerged after World War I, characterized by geometric shapes, bold colors, and luxurious materials. It emphasizes glamour, order, and machine-age modernity. Frequently used in architecture, fashion, interior design, and product design, Art Deco is associated with progress, technology, and opulence. Iconic examples include the Chrysler Building and works by Émile-Jacques Ruhlmann.