Allied occupation, party politics were banned in Sicily. Most institutions were destroyed, with the exception of the police and carabinieri, and the American occupiers had to build a new order from scratch. As Fascist mayors were deposed, the Allied Military Government of Occupied Territories (AMGOT) simply appointed replacements. Many turned out to be mafiosi, such as Calogero Vizzini and Giuseppe Genco Russo. They could easily present themselves as political dissidents, and their anti-communist position gave them additional credibility. Mafia bosses reformed their clans, absorbing some of the marauding bandits into their ranks. The changing economic landscape of Sicily shifted the Mafia's power base from rural to urban areas. The Minister of Agriculture – a communist – pushed for reforms in which peasants were to get larger shares of produce, be allowed to form cooperatives and take over badly used land, and remove the system by which leaseholders (known as "gabelloti") could rent land from landowners for their own short-term use. Owners of especially large estates were to be forced to sell off some of their land. The Mafia had connections to many landowners and murdered many socialist reformers. The most notorious attack was the Portella della Ginestra massacre, when 11 people were killed and 33 wounded during May Day celebrations on May 1, 1947. The bloodbath was perpetrated by bandit Salvatore Giuliano, who was possibly backed by local Mafia bosses. In the end, though, they were unable to stop the process, and many landowners chose to sell their land to mafiosi, who offered more money than the government. In the 1950s, a crackdown in the United States on drug trafficking led to the imprisonment of many American mafiosi. Cuba, a major hub for drug smuggling, was taken over by Fidel Castro and associated communists. In 1957 American mafia boss Joseph Bonanno returned to Sicily to franchise his heroin operations to the Sicilian clans. Anticipating rivalries for the lucrative American drug market, he negotiated the establishment of a Sicilian Mafia Commission to mediate disputes. Sack of Palermo The post-war period saw a huge building boom in Palermo. Allied bombing in World War II had left more than 14,000 people homeless, and migrants were pouring in from the countryside, so there was a huge demand for new homes. Much of this construction was subsidized by public money. In 1956, two Mafia-connected officials, Vito Ciancimino and Salvatore Lima, took control of Palermo's Office