immigrant parents in Park City, Utah, became an American art photographer, primarily known for his Hollywood portraits in the 1920s-1940s in the pictorialist style. Dance The three Christensen brothers: Lew, Harold, and Willam are well known in the history of American ballet. The three carved out careers as choreographers, teachers and directors, and clearly helped ballet flourish in the United States. Willam Christensen (1902–2001) especially, was the founder of the San Francisco Ballet. The three brothers were born into a Danish-American Mormon family in Brigham City, Utah. Design Peter Bentzon, he was a Danish West Indies-born American master silversmith and the only early-American silversmith of African-ancestry whose silverwork has been identified. He produced his masterpieces on both St. Croix and in Philadelphia, Jens Risom a craftsman from Copenhagen, who emigrated in 1939, was renowned for his furniture design, as co-founder of the Hans Knoll Furniture Company, and as a trustee at the Rhode Island School of Design. Tage Frid, another Danish furniture designer, who came to the United States in 1948, is likewise known for his wood furniture design and professorship at the Rhode Island School of Design from 1962-1985. In the field of metalsmithing, John Prip, who was born in New York to a Danish father and an American mother, performed his apprenticeship in Denmark and returned to the United States where he became known for his silverwork and design. Many years after creation, some of Prip's designs are still in production by the Reed & Barton Silver Company. Prip taught at both the Rochester Institute of Technology and the Rhode Island School of Design. Food According to Louis' Lunch, the hamburger was created by the owner, Louis Lassen (1865 Denmark - March 20, 1935 New Haven, Connecticut) in 1900 in response to a customer's hurried request for a lunch to go. Louis' Lassen's restaurant is recognized in the Library of Congress as the origin of the hamburger, but other claimants and detractors exist. Science Jens Clausen revolutionized the study of evolutionary genetics in botany, while Erik Erikson revolutionized developmental psychology with his theory on social development. Niels Ebbesen Hansen was a noted pioneer in plant breeding. Charles Christian Lauritsen was a physicist. In the final months of World War II he was part of the team of scientists who invented the atomic bomb. Mikkel Frandsen was a physical chemist noted for his experiments involving chemical thermodynamics, oil, and