In the 1960s, Merz’s work with energy, light and matter placed him in the movement that Germano Celant named Arte Povera, which, together with Futurism, was one of the most influential movements of Italian art in the 20th century. In 1968 Merz began to work on his famous igloos and continued throughout his life, revealing the prehistoric and tribal features hidden within the present time and space. He saw the mobility of this typical shelter for nomadic wandering as an ideal metaphor for the space of the artist. The neon words on his igloos are hallmark Italian phraseology: like "rock ‘n’ roll," they have the power of being the more than catch phrases or slogans, but the voice of his time in history. His first of the dome-shaped structures, "Giap's Igloo," in 1968 was decorated with a saying by General Vo Nguyen Giap of North Vietnam: If the enemy masses his forces, he loses ground. If he scatters, he loses force.
From the late 1970s to the end of his career, Merz joined many artists of his generation in returning periodically to more conventional media. In Le Foglie (The Leaves) (1983–84), measuring over 26 feet across, gold leaf squares are scattered around two large asymmetrical leaf-like forms. He even, occasionally, carved in marble, with which in 2002 he made five statues displayed from the windows of a building at the International Sculpture Biennale in Carrara. Merz said: "Space is curved, the earth is curved, everything on earth is curved" and subsequently produced large curvilinear installations like the one at the Guggenheim in New York. This retrospective was the artist's first major museum show in the United States. These last works are formally transcendent and unusually light. His site-specific works in archaeological sites redeem spaces from touristy tedium with a single neon line, which serves as source of aesthetic inspiration.Wikipedia