The book "The Accountant's Story" which Pablo Escobar's brother published, Roberto Escobar, discusses how his brother became rich. It explains how he rose from poverty. The book also says how Escobar became one of the richest men of the world. He led the largest and most successful criminal enterprise in world history. At times, the Medellín drug cartel was smuggling 15 tons of cocaine a day. This was worth more than half a billion dollars. They sent it to the United States and sold it there. According to Roberto Escobar, Pablo Escobar's accountant, they spent $2,500 a month for buying rubber bands to wrap the stacks of cash. They had more illegal money than they could store in banks. Therefore, they stored the bricks of cash in their warehouses. About 10% were destroyed each year because of rats.