ALH 84001 is the Antarctic meteorite from Mars that became famous for possible fossil evidence.
The meteorite was discovered in the Allan Hills region of Antarctica in 1984 and is classified as a Martian orthopyroxenite. Scientists concluded that it originated on Mars because its trapped gases match the distinctive composition of the Martian atmosphere measured by NASA’s Viking landers. A large impact eventually ejected the rock from Mars, and it later fell to Earth as a meteorite.
In 1996, a team announced that ALH 84001 contained features that might be fossilized evidence of ancient microbial life. The claim attracted worldwide attention because it involved tiny structures and minerals that some researchers interpreted as biological. Subsequent research has shown that the features can also be produced by non-biological geological and chemical processes.
ALH 84001 therefore does not provide universally accepted proof of life on Mars. Nakhla is another famous Martian meteorite, while Hoba is an iron meteorite from Earth and not from Mars.