US' National Aeronautics and Space Administration (NASA) is examining a rock from a Bulgarian hill near Gorna Oryahovica in the north.
The tests are part of NASA's "Rock Around the World" program for collecting rock samples from the Earth and comparing them with the samples that were tested on Mars.
People from all parts of the world are urged to submit a rock that has been removed from the ground of its natural environment, so that scientists could verify their hypotheses of similarities between the Martian and Earth rocks.
Bulgaria's first sample comes from the hill "Kamyka" (The Rock), near Gorna Oryahovica. It has been submitted by Ivan and Margarita Kyrdzhilovi and will be tested by the same tools that the two Mars exploration rovers- Spirit and Opportunity were equipped with.