The history of art dates back to pre-historic times when Paleolithic humans created objects, such as wall paintings and sculptures, to represent their beliefs and culture. People have used art to tell stories, illustrate their ideas, and to express themselves throughout human history. As civilizations evolved and grew, so did the need for more-complex art forms, and the development of technology and communication enabled art forms such as painting and sculpture to be shared more widely. The Renaissance ushered in a new era of art that focused on realism and humanism. This period opened up the possibility of new artistic styles to be explored, from Romanticism to the Baroque and Abstract Expressionism. In the 20th century, modernism and postmodernism revolutionized art for generations to come, and the range of art forms and styles now available is immense. Contemporary art continues to explore the boundaries of what it means to be an artist, pushing the boundaries of traditional genres and creating new ways of expressing and viewing the world.