progress. The studies and photos were often loaned for other exhibitions, but until 1981, Guernica itself remained at MoMA. During the Vietnam War, the room containing the painting became the site of occasional anti-war vigils. These were usually peaceful and uneventful, but on 28 February 1974, Tony Shafrazi—ostensibly protesting Second Lieutenant William Calley's petition for habeas corpus following his indictment and sentencing for the murder of 109 Vietnamese civilians during the My Lai massacre—defaced the painting with red spray paint, painting the words "KILL LIES ALL". The paint was removed with relative ease from the varnished surface. Establishment in Spain As early as 1968, Franco had expressed an interest in having Guernica come to Spain. However, Picasso refused to allow this until the Spanish people again enjoyed a republic. He later added other conditions, such as the restoration of "public liberties and democratic institutions". Picasso died in 1973. Franco, ten years Picasso's junior, died two years later, in 1975. After Franco's death, Spain was transformed into a democratic constitutional monarchy, ratified by a new constitution in 1978. However, MoMA was reluctant to give up one of its greatest treasures and argued that a monarchy did not represent the republic that had been stipulated in Picasso's will as a condition for the painting's delivery. Under great pressure from a number of observers, MoMA finally ceded the painting to Spain in 1981. The Spanish historian Javier Tusell was one of the negotiators. Upon its arrival in Spain in September 1981, it was first displayed behind bomb-and bullet-proof glass screens at the Casón del Buen Retiro in Madrid in time to celebrate the centenary of Picasso's birth, 25 October. The exhibition was visited by almost a million people in the first year. Since that time there has never been any attempted vandalism or other security threat to the painting. In 1992, the painting was moved from the Museo del Prado to a purpose-built gallery at the Museo Nacional Centro de Arte Reina Sofía, both in Madrid, along with about two dozen preparatory works. This action was controversial in Spain, since Picasso's will stated that the painting should be displayed at the Prado. However, the move was part of a transfer of all of the Prado's collections of art after the early 19th century to other nearby buildings in the city for reasons of space; the Reina Sofía, which houses the capital's national collection