On March 21,1963 Alcatraz closed. The institution was too expensive to continue operating. An estimated $3-5 million was needed just for restoration and maintenance work to keep the prison open. That figure did not include daily operating costs - Alcatraz was nearly three times more expensive to operate than any other Federal prison. The major expense was caused by the physical isolation of the island. This isolation meant that everything (food, supplies, water, fuel, etc.) had to be brought to Alcatraz by boat. For example, the island had no source of freshwater, so nearly one million gallons of water had to be barged to the island each week. The Federal Government found that it was more cost-effective to build a new institution than to keep Alcatraz open. After the prison closed, Alcatraz was basically abandoned. Many ideas were proposed for the island, including a monument to the United Nations, a West Coast version of the Statue of Liberty, and a shopping center/hotel complex. In 1969, the island again made news when a group of Native American Indians claimed Alcatraz as Indian land with the hope of creating a Native American cultural center and education complex on the island. In June 1971, Federal Marshals removed the remaining Native Americans from the island.