Now that "Deep Throat" has been identified as a 91-year-old California grandfather, aficionados of unsolved mysteries have to look elsewhere. Luckily for them, there are plenty of places to look.

　　Even after Tuesday's revelation that former FBI No. 2 Mark Felt was the Watergate super-source "Deep Throat," there are still unknowns swirling around the scandal that brought down President Richard Nixon in 1974.

　　The main question remaining is what information was contained -- and erased -- in the 18 1/2 minute gap in a White House tape recording. The tape, made by Nixon's secretary, Rose Mary Woods, contained a discussion between the president and his chief of staff, H.R. Haldeman, pertaining to Watergate.

　　Woods shot to notoriety for her inadequate explanations of how she came to erase part of the tape. She never told what the tape held before her death.

　　A more contemporary Washington mystery is the source of the leak that led columnist Robert Novak to identify a CIA operative named Valerie Plame, an expert on weapons of mass destruction.

　　Novak mentioned Plame by name in a July 14, 2003, column critical of Plame's husband, retired diplomat Joseph Wilson, after Wilson reported an Iraqi purchase of uranium "yellowcake" from Niger was highly unlikely. Wilson's report went counter to some in the Bush administration who sought a link between Iraq and weapons of mass destruction.

　　Novak has not said where he got the information, but denied it was a "planned leak," and said he was never told revealing Plame's identity would endanger her or anyone else. A special prosecutor is investigating the case.

　　The mystery that set Washingtonians buzzing in the summer of 2001 was the disappearance of 24-year-old Chandra Levy, a government intern who had a relationship with Rep. Gary Condit, a California Democrat. Levy's skeletal remains were found in a city park in 2002. How they got there remains unknown.

　　Beyond Washington, there are historical mysteries that still resonate. Many observers wonder whether Lee Harvey Oswald acted alone on Nov. 22, 1963, when President John F. Kennedy was assassinated in Dallas.

　　The mystery surrounding former Teamsters union leader Jimmy Hoffa revolves around what happened to his body after he disappeared from a Michigan parking lot in 1975. The presumption is he was killed by the Mafia , but the whereabouts of his remains are unknown.

　　The final fate of pioneer aviator Amelia Earhart has never been discovered, although theories abound. She was last heard from on July 2, 1937, on the Pacific leg of her attempt to be the first woman to fly around the globe. Extensive rescue attempts turned up nothing.