Leo /ˈliːoʊ/ is one of the constellations of the zodiac, lying between Cancer to the west and Virgo to the east. Its name is Latin for lion, and to the ancient Greeks represented the Nemean Lion killed by the mythical Greek hero Heracles (known to the ancient Romans as Hercules) as one of his twelve labors. Its symbol is (Unicode ♌). One of the 48 constellations described by the 2nd century astronomer Ptolemy, Leo remains one of the 88 modern constellations today, and one of the most easily recognizable due to its many bright stars and a distinctive shape that is reminiscent of the crouching lion it depicts. The lion's mane and shoulders also form an asterism known as "the Sickle," which to modern observers may resemble a backwards "question mark."