Christo attended the Fine Arts Academy in Sofia, Bulgaria, and had begun working with the Burian Theatre in Prague when the Hungarian Revolution of 1956 broke out. He fled to Vienna, where he studied for a semester, and then, after a brief stay in Switzerland, moved to Paris and began exhibiting his works with the "nouveaux réalistes". While working there as a portrait artist, Christo met Jeanne-Claude de Guillebon, whom he married in 1959. Jeanne-Claude was once described as her husband’s publicist and business manager, but she later received equal billing with him in all creative and administrative aspects of their work. In 1964 the pair relocated to New York City, where their art was seen as a form of "Arte Povera". Christo’s earliest sculptures were composed of cans and bottles. Christo and Jeanne-Claude’s first collaborative works included "Dockside Packages" in Cologne in 1961, "Iron Curtain—Wall of Oil Drums" in Paris in 1962, and "Corridor Store Front" in New York City in 1968. In the same year, they also completed a suspended 5.600 metre “air package” over Minneapolis and “wrapped buildings” in Bern, Chicago and Spoleto in Italy. Their monumental later projects included "Valley Curtain" in Rifle Gap in 1972, "Running Fence" in 1976, and "Surrounded Islands" in Biscayne Bay in 1983. In 1985 in Paris, they wrapped the "Pont Neuf bridge" in beige cloth. In a 1991 project, the couple installed 1,340 giant blue umbrellas across the Sato River valley in Japan and 1,760 giant yellow ones in Tejon Pass, California. Four years later they wrapped the "Reichstag" in Berlin in metallic silver fabric. "The Gates" in Central Park, New York City, 1979–2005 was unveiled in 2005. Stretching across 37 km of walkway in Central Park, the work featured 7,503 steel gates that were 5 metres high and decorated with saffron-coloured cloth panels. "The Gates" was on display for 16 days and attracted more than four million visitors. Christo and Jeanne-Claude’s huge, usually outdoor sculptures are temporary and involve hundreds of assistants in their construction. Seen as they are by all manner of passersby, including those who would not necessarily visit museums, these works force observers to confront questions regarding the nature of art. As the scope of the projects widened, increased time was needed for planning and construction phases, the securing of permits, and environmental- impact research. For each project, they formed a corporation, which secured financing and sold the primary models and sketches. Most installations were documented in print and on film, and the materials that created them were sold or given away after the projects were dismantled.