For the 19th century, the world beneath the sea played much the same role that "outer space" played for the 20th. The ocean depths were at once the ultimate scientific frontier and "the reservoir of the soul." The central figure of PROTEUS is biologist and artist Ernst Haeckel. Haeckel found himself torn between science and art, materialism and religion, rationality and passion, outer and inner worlds. Through his discoveries beneath the sea, Haeckel eventually reconciled these dualities, bringing science and art together in a unitary, almost mystical vision. The key to Haeckel's vision was a tiny undersea organism called the radiolarian, one of the earliest forms of life.