Artist Andy Goldsworthy is best known for working alone in nature, making fragile, temporary sculptures from leaves, rocks, even ice. The sculptor works quietly for hours in each place, a process captured in the 2001 documentary Rivers and Tides. Photographs of Goldsworthy's work hang in galleries and museums around the world. His latest project is a permanent piece in the center of Washington, D.C. It's the first new work commissioned by the National Gallery of Art in 26 years. Goldsworthy mastered optics and engineering to create a series of domes constructed of slabs of slate designed to hold together permanently...