With cobalt waters harbouring eerie, coral-like formations, this archipelago of lakes in Mexico's searing Chihuahuan desert has always had an other-worldly appearance. Now top researchers at the US National Aeronautics and Space Administration (NASA) say the calcified clumps of primitive bacteria lurking in its pools could provide important clues in their search for extra-terrestrial life. The network of 170 cactus-ringed lagoons around the town of Cuatro Cienegas have intrigued evolutionary biologists for decades because their fish, snail and turtle species rival the galapagos islands in their uniqueness. Scientists from NASA's trobiology institute have begun studying the lakes' ancient formations called stromatolites - rock structures formed by layers of algae that trap silt.