at the house, Mrs. Rockefeller offered her the bed, and Mrs. Bush responded, "you are always welcome in this house, but there's no need to bring your own bed." The Rockefellers did leave a lithograph called "The Great Ignoramus", several antique Korean and Japanese chests, and nearly a dozen other pieces. When the Mondales occupied the house, Joan Mondale introduced more saturated upholstery and wall colors and contemporary art. Like the Rockefellers, the Mondales brought some Asian antiques into the house. The Bush family, working with interior decorator Mark Hampton, used a palette of celadon, lime green, and light blue. The Quayles removed the lime green and used off-white. The Gores oversaw a complete redecoration, the addition of a new dining-room table, new furniture for the library, and a substantial renovation of the grounds and porches to make them more suitable for outdoor entertaining. Immediately before the Cheneys moved in, some needed work on the air conditioning and heating was performed and the interiors were repainted. The Cheneys brought several pieces of contemporary art into the house. Privacy and security Privacy Unlike the White House, Number One Observatory Circle, and the surrounding Naval Observatory, do not offer any public tours. Underground bunker In December 2002, following the September 11 attacks, neighbors of the Number One Observatory Circle, then inhabited by Cheney, complained of loud "blasts" and construction noises. Occurring several times and lasting up to five seconds, the vibrations were able to knock mirrors off the walls of some nearby residences. Neighbors who complained about the construction received a letter from the observatory's superintendent reading, "Due to its sensitive nature in support of national security and homeland defense, project-specific information is classified and cannot be released." It was widely speculated that a nuclear bunker was being constructed. In 2009, recently inaugurated Vice President Joe Biden reportedly revealed the existence of an underground "9/11" bunker beneath the house. Elizabeth Alexander, Biden's press secretary, explained the following day, "What the vice president described in his comments was not—as some press reports have suggested—an underground facility, but rather, an upstairs work space in the residence, which he understood was frequently used by Vice President Cheney and his aides." The Christian Science Monitor suggested that Biden was actually referring to a tunnel which leads to one of the Navy-operated telescopes on the grounds. See also White House – the official residence of the president