Artworks that feature young adults—their physical appearances, emotions, and habits—have been a regular and evolving theme in the history of art. In ancient Greece and Rome, an idealized image of youthful beauty emerged in the form of nude sculptures, which reappeared as a focus centuries later in iconic works by Renaissance artists such as Donatello, Michelangelo, Bernini, and Canova. These were associated with various narratives of physical strength, love, and desire. While many artists have continued to work with notions of physical beauty in the 20th century, a parallel tendency has been the exploration of countercultural identities, and young men and women engaged in sexual acts. Photographers in particular, including Larry Clark, Nan Goldin, Robert Mapplethorpe, and Ryan McGinley, have explored taboo subjects such as drug use and sexuality in youth culture, often through the documentation of their own friends and experiences. Other explorations of adolescence in art have been less direct; in China, artists of the Post-’70s Ego Generation explore their lives and identities in the wake of the country's one-child policy.