Arnaldo Pomodoro's 'Sphere No. 6 (Sphere within a Sphere)' is a monumental bronze sculpture created between 1963 and 1965, representing one of the most iconic works in the artist's celebrated series of spherical forms. The polished exterior shell is dramatically fractured to expose an intricate labyrinthine interior of gears, rods, and geometric mechanisms, embodying Pomodoro's signature investigation into the chaos concealed beneath perfect surfaces. This work entered the collection of the Hirshhorn Museum and Sculpture Garden as a gift from Joseph H. Hirshhorn in 1966, underscoring its early institutional recognition and significant provenance. It is a landmark example of Italian postwar sculpture and a cornerstone work for any serious collection of modern and contemporary art.