21Baikal Seals
It remains a scientific mystery how Baikal Seals originally came to Lake Baikal, hundreds of kilometers from any ocean. Estimated to have inhabited Lake Baikal for some two million years, the Baikal Seal is the only true freshwater seal on Earth.
22La Mancha Negra
There is a mysterious expanding black goo called La Mancha Negra (the black stain) that covers parts of roads in Caracas, Venezuela. Millions of dollars have been spent researching it, yet the cause is still unknown. 1,800 people have died in auto accidents due to the goo.
23Isdal Woman
In 1970, a group of hikers outside of Bergen, Norway, suddenly came upon the charred, naked corpse of a woman in the middle of the Isdalen Valley. The woman was nicknamed the Isdal Woman and her story remains one of Norway’s deepest mysteries.
24D.B. Cooper
There is only one unsolved airline hijacking case in the history of the U.S. The hijacker (D.B. Cooper) parachuted out of the plane after receiving his demands, and was described as "thoughtful and polite" by his hostage.
25Pickle Jar
Since 2012, there has been a pickle jar that sits on the guardrail on the I-270 North in Des Peres, Missouri. Every time the jar falls, breaks, or disappears, it is always replaced, but who does it remains a mystery.
