Modern dance originated in the early 1900s in the United States as a rebellion against restrictive classical ballet. It uses loose, improvised movements to interpret emotions and tell stories through dance rather than rigid steps. Pioneers like Martha Graham, Ruth St. Denis, Isadora Duncan, and Loie Fuller helped establish modern dance by incorporating influences from other cultures and innovating the use of lighting, floor work, and other techniques. While initially controversial, modern dance became more widely accepted and influential over time.