Watch art21 Season 5 Episode 4 Online

Artists who tackle projects that are complex and/or vast in scope are featured, including Ethiopian-American painter Julie Mehretu, who's shown creating a large work about the history of market-based capitalism; John Baldessari, who mixes photomontage, painting and language in his pieces; Korean-born Kimsooja, whose art combines techniques of video, performance and installation; and Allan McCollum, who creates large quantities of almost identical objects.