Friedrich Froebel developed the concept of kindergarten in the early 19th century based on the principle that play and exploration are essential for early childhood education. He opened the first kindergarten in 1840 using structured play activities, songs, and gardening. While his ideas spread widely and influenced many educators, kindergartens have since evolved away from his strict system toward more open-ended, creative play. Froebel believed that play is the highest form of learning for young children and allows them to freely express themselves.