Every year thousands of people go missing all over the world. Some of them are found while some of them remain missing for long periods of time, and some forever. Among them, the most intriguing cases are those where people just disappear. In most of these sudden disappearance cases, there doesn’t exist a single clue and the person appears to have vanished into thin air. Here are 10 such people who disappeared without a trace.

1 Jim Sullivan

In 1969, a musician named Jim Sullivan recorded an album called U.F.O., which featured strange lyrics about leaving his family and being abducted by aliens. Sullivan disappeared six years later without a trace, the only piece of evidence being his abandoned car found on a desert road.

American singer-songwriter James Anthony Sullivan (also known as Jim Sullivan) made headlines in 1975 when he disappeared under mysterious circumstances. On March 4, 1975, he left Los Angeles to drive to Nashville alone in his Volkswagen Beetle.

The next day he checked into a motel in Santa Rosa, New Mexico but did not sleep there. The following day he was seen again about 26 miles away at a remote ranch owned by the Gennetti family. He’s never been seen or heard from ever again. His car was later found abandoned at the ranch and his guitar was in it.

The mysterious nature of his disappearance is amplified by his cryptic lyrics in the album U.F.O. In the album he talks about long highways, leaving his family behind, and being abducted by aliens in the desert. The lyrics have an eerie similarity to the actual situation leading to Jim’s disappearance. (1,2)

2 Fredrick Valentich

In 1978, pilot Frederick Valentich and his plane disappeared under mysterious circumstances. In his last radioed message, he mentions a strange aircraft hovering over him.

On the evening of Saturday, 21 October 1978, pilot Fredrick Valentich was flying over Bass Strait in Australia. At 7:06 p.m., Valentich radioed Melbourne Flight Service and reported that an unidentified aircraft was following him at 4,500 feet. He was told there was no known traffic at that level. Valentich said he could see a large, unknown aircraft which appeared to be illuminated by four bright landing lights.

Valentich then reported that the aircraft was approaching him from the east. Then he reported that the aircraft was “orbiting” above him and that it had a shiny metal surface and a green light on it. Soon he started experiencing engine problems and he radioed, “It isn’t an aircraft.” After that his transmission was interrupted by an unidentified noise described as being “metallic, scraping sounds” before all contact was lost.

Soon, a sea and air search was undertaken, and the search encompassed over 1,000 square miles but proved to be of no avail. The last radioed message of Valentich has sparked speculation of an alien abduction. (1,2)

3 Madeleine McCann

Madeleine McCann, age 3, disappeared on the evening of 3 May 2007 from her bed in a holiday apartment in Portugal. Her disappearance was heavily reported by global media but still, her whereabouts remain unknown.

In May 2007, Madeleine McCann, her siblings, and her parents were in Portugal on a holiday. They were along with a group of family friends and their children. On May 3, 2007, her parents, Gerry and Kate, left their three children – including toddler twins Sean and Amelie – sleeping in their apartment while they dined at a tapas bar 120 meters away.

At 10 p.m. that evening, Kate returned to check on the kids and discovered that Madeleine was not in her bed and was missing. Fearing the worst, Kate told her dazed husband and their friends that somebody had taken their defenseless three-year-old.

Patrol officers arrived at about 11 p.m. A search operation including both police and Ocean Club’s members proved fruitless. The disappearance of Madeleine gained huge attention and became one of the most heavily reported missing-person cases in modern history.

Scores of theories popped up, and one witness even claimed to have seen a man carrying a child walking towards the beach. The McCanns were subjected to intense scrutiny and baseless allegations of involvement in their daughter’s death. Three-year-old Maddie’s whereabouts remain a mystery as even an £11 million police investigation has failed to provide answers. (1,2,3)

4 Ray Gricar

Ray Gricar, the American District Attorney originally assigned to the “Sandusky Case,” disappeared mysteriously in 2005. His laptop was later found in a river with its hard drive missing.

On April 15, 2005, attorney Ray Gricar took a day off. At 11:30 a.m., he called his girlfriend Patricia Fornicola to say he was taking a drive on Route 192. When Gricar failed to return home late that evening, his girlfriend reported him missing. The following day, investigators identified the car driven by Ray Gricar in an antique store parking lot in Lewisburg, Pennsylvania. The car contained his cell phone but not his laptop computer, nor his keys, nor his wallet.

On July 30, 2005, fishermen discovered Gricar’s laptop computer in the Susquehanna River beneath a bridge between Lewisburg and Milton. Analysis of the laptop showed that its hard drive was missing. Two months later, someone recovered a hard drive on the banks of the Susquehanna River about 100 yards from the location of the laptop. Investigator believed it to be the hard drive of Gricar’s laptop, but it was badly damaged and all attempts to recover the data failed.

Later, investigators revealed that a search of his home computer yielded a history of Internet searches for phrases like “how to wreck a hard drive.” Some believe that his disappearance is related to the Sandusky Case in which Gricar had chosen not to prosecute the then-Penn State assistant coach, Jerry Sandusky, after reports surfaced that he had inappropriate interactions with a boy. (1,2)

5 Jim Gray

Jim Gray, a Microsoft scientist & Turing Award winner, left San Francisco Bay by sailboat to scatter his mother’s ashes at the Farallon Islands. He was reported missing when he failed to return later the same day. Despite one of the most thorough search and rescue missions, neither  Gray nor his yacht were ever found.

On Sunday, January 28, 2007, American computer scientist Jim Gray took what should have been a short, solo sailing trip to the Farallon Islands near San Francisco to scatter his mother’s ashes. At 10:30 a.m., he called his wife, Donna Carnes, from his 40-foot yacht Tenacious. A couple of hours later, his sailboat was spotted by a naturalist from Southeast Farallon Island. Then Gray and his boat vanished.

The Coast Guard received no Mayday call. Even Gray’s EPIRB, an emergency radio beacon designed to broadcast a homing signal if it sinks, stayed silent. No sailors in the area reported seeing the boat adrift, and not a single life vest, flashlight, or scrap of debris belonging to Tenacious washed up on local beaches. After being missing for five years, Gray was legally assumed to have died at sea on January 28, 2012. (1,2)