Gone without a trace: 6 missing people 

The enduring mystery of where Jimmy Hoffa is buried and the latest futile search for his remains this week have illustrated the continuing fascination with famous disappearances.

Hoffa was last seen alive in suburban Detroit on July 30, 1975. For 38 years, authorities have searched multiple sites for his body. The latest search, conducted by the FBI in a field in Oakland Township, Mich. on a tip from a former Detroit Mafia boss, ended the same way as the rest: On Wednesday, the search ended, and no remains were found.

Story: Why we've been obsessed with Hoffa for 38 years

The late Teamsters union boss isn't the only missing person who has eluded authorities: Remember these notable unsolved disappearances?

Amelia Earhart

Amelia Earhart is one of the most iconic missing persons of all time.

In one of the most famous disappearances of the 20th Century, Earhart was attempting to become the first woman to fly around the world when she and her navigator, Fred Noonan, went missing over the Pacific Ocean on June 2, 1937. Investigators determined that she ran out of fuel and crashed into the water, and she was declared legally dead on Jan. 5, 1939.

There has never been a definitive explanation of why the famous aviator's plane went down, and conspiracy theories have ranged from Earhart being a secret agent spying on the Japanese to her quietly returning to the United States under a fake identity.

Finding her downed plane continues to be a fixation for several adventurers, including The International Group of Historic Aircraft Recovery. The organization spent $2.2 million in 2012 searching a remote area in the Pacific Ocean off Hawaii in an unsuccessful attempt to locate the wreckage.

D.B. Cooper

Anonymous / Today
An artist's sketch of 'Dan Cooper' or 'D.B. Cooper,' from the recollections of passengers and crew of the jet he hijacked.

An unknown passenger calling himself Dan Cooper hijacked a Northwest Orient flight on Nov. 24, 1971, wearing a dark suit, raincoat and black sunglasses and telling a stewardess he had a bomb in his briefcase. He demanded $200,000 in cash and four parachutes and forced the plane to land in Seattle. He forced the pilot to fly toward Mexico City, and during the flight, he parachuted out of the plane into a thunderstorm.

An early report identified him as “D.B. Cooper,’’ which is how he has become immortalized. He was never seen again, and his body has never been found. The FBI has ruled out more than 1,000 possible suspects over the years and believes he most likely died while parachuting into the storm.

A stack of almost $6,000 in cash from the ransom money given to Cooper was found in 1980 by a young boy on a bank of the Columbia River near Vancouver, Washington. His mystery continues to live on, including being name-checked with the line “And to D.B. Cooper and the money he took” in the 1998 hit “Bawitdaba” by Kid Rock.

Oscar Zeta Acosta

Better known as writer Hunter S. Thompson’s sidekick, immortalized as Samoan attorney Dr. Gonzo in the Thompson classic “Fear and Loathing in Las Vegas,” Acosta was an attorney and Chicano Movement activist. He disappeared while traveling off the coast of Mazatlan, Mexico, in 1974 at age 39.

Acosta called his son, Marco, before boarding a boat in Mexico. Thompson speculated at the time that he was either the target of a political assassination or murdered by drug dealers. He is presumed dead.

Acosta’s body was never found, although rumors began to surface that he was alive in Miami. Thompson wrote an obituary for his friend, titled “Fear and Loathing in the Graveyard of the Weird: The Banshee Screams for Buffalo Meat,’’ to quell any rumors.

In 1998, Benicio del Toro played Dr. Gonzo in the film adaptation of "Fear and Loathing," which also starred Johnny Depp as the fictionalized Thompson character Raoul Duke.

Keith Bedford / Today
Etan Patz, in his missing poster.

Etan Patz

Patz disappeared in lower Manhattan on May 25, 1979 at age six during a walk to the school bus and has not been seen since. His disappearance was an impetus for the campaign to put photos and information about missing children on milk cartons, and he was the first missing child to ever appear on one.

The New York County District Attorney’s office reopened the case of his disappearance in 2010. In April of 2012, an apartment just a block from his SoHo home was searched by authorities for remains or belongings. Authorities removed concrete slabs from the basement along with some trash bins, but nothing conclusive was found.

Bison Dele

Formerly known as Brian Williams, Dele was a center who played on the Michael Jordan-led Chicago Bulls team that won the NBA championship in 1997 and later played with the Detroit Pistons.

Ezra Shaw / Today
Bison Dele, here playing for the Detroit Pistons in 1999, disappeared in 2002.

In July of 2002, he disappeared while sailing on the South Pacific on his boat, the Hakuna Matata. He was with his girlfriend, brother and skipper Bertrand Saldo, and only his brother, Miles Dabord (formerly Kevin Williams) was on the boat when it reached port in Tahiti on July 20.

The FBI suspected Dabord killed Dele, Saldo and Dele’s girlfriend and threw them overboard, but never solved the mystery because Dabord committed suicide in September of 2002.

Ray Gricar

As district attorney for Centre County, Penn., in 1998, Gricar declined to press charges of child sexual abuse against Penn State football assistant Jerry Sandusky, almost 15 years before Sandusky was convicted of 45 counts of sexual abuse in June of 2012.

Gricar disappeared on April 15, 2005. His red Mini Cooper and cell phone were found a day later in a parking lot in Lewisburg, Penn., near two bridges over the Susquehanna River. In July 2005, a fisherman found his laptop in the Susquehanna River; the damaged hard drive was later recovered on the banks of the river.

On July 25, 2011, he was declared legally dead. His body has never been found.