Following the Sept. 11 terrorist attacks, Vice President Dick Cheney disappeared and was whisked off to a "secure, undisclosed location" to protect his safety. But Cheney never confirmed where exactly he hunkered down.

That is, until now.

Cheney confirms in his new memoir, "In My Time," that some of the speculation was correct--one of his "undisclosed locations" was his residence in Northwest Washington, D.C., the Washington Post reports.

Which, in turn, means Joe Biden was right.

Vice President Biden told the world in 2009 that he discovered the bunker beneath his home during a tour of his new house. Biden revealed during the 2009 Gridiron Club dinner that the room was located "behind a massive steel door secured by an elaborate lock with a narrow connecting hallway lined with shelves filled with communications equipment," Newsweek's Eleanor Clift wrote at the time.

In the book, Cheney says that in addition to his D.C. home, the other undisclosed locations were at his home in Wyoming and at Camp David, the presidential retreat.

Cheney writes that he was surprised by the interest in the location, noting a "Saturday Night Live" skit that placed him in a cave in Afghanistan, according to the Post.

Cheney's memoir contains a cadre of additional tidbits. They include:

• After undergoing heart surgery in 2010, Cheney was unconscious for weeks, the New York Times reports. During that time, Cheney experienced a "prolonged, vivid dream that he was living in an Italian villa, pacing the stone paths to get coffee and newspapers," according to the Times.

• Cheney kept a secret, undisclosed resignation letter locked in a safe in case his health suddenly failed.

• He urged Bush to bomb a suspected Syrian nuclear reactor site in June 2007, but none of the president's other advisers agreed to the plan.

• Cheney offered to remove himself from the Republican ticket on three occasions before the 2004 election.

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