the top. Each anchorage weighs . The Manhattan anchorage rests on a foundation of bedrock while the Brooklyn anchorage rests on clay. The anchorages both have four anchor plates, one for each of the main cables, which are located near ground level and parallel to the ground. The anchor plates measure , with a thickness of and weigh each. Each anchor plate is connected to the respective main cable by two sets of nine eyebars, each of which is about long and up to thick. The chains of eyebars curve downward from the cables toward the anchor plates, and the eyebars vary in size depending on their position. The anchorages also contain numerous passageways and compartments. Starting in 1876, in order to fund the bridge's maintenance, the New York City government made the large vaults under the bridge's Manhattan anchorage available for rent, and they were in constant use during the early 20th century. The vaults were used to store wine, as they were kept at a consistent temperature due to a lack of air circulation. The Manhattan vault was called the "Blue Grotto" because of a shrine to the Virgin Mary next to an opening at the entrance. The vaults were closed for public use in the late 1910s and 1920s during World War I and Prohibition but were reopened thereafter. When New York magazine visited one of the cellars in 1978, it discovered a "fading inscription" on a wall reading: "Who loveth not wine, women and song, he remaineth a fool his whole life long." Leaks found within the vault's spaces necessitated repairs during the late 1980s and early 1990s. By the late 1990s, the chambers were being used to store maintenance equipment. Towers The bridge's two suspension towers are tall with a footprint of at the high water line. They are built of limestone, granite, and Rosendale cement. The limestone was quarried at the Clark Quarry in Essex County, New York. The granite blocks were quarried and shaped on Vinalhaven Island, Maine, under a contract with the Bodwell Granite Company, and delivered from Maine to New York by schooner. The Manhattan tower contains of masonry, while the Brooklyn tower has of masonry. Each tower contains a pair of Gothic Revival pointed arches, through which the roadways run. The arch openings are tall and wide. The tops of the towers are located above the floor of each arch