The constellation Leo has been known since antiquity and was included as one of the constellations of Ptolemy's zodiac in the 2nd century CE. In the Northern Hemisphere, Leo rises above the horizon on or around the first day of spring.
Leo lends its name to the annual Leonid meteor shower that peaks in November and to the January Leonids, which peak in the first week of the month. Viewed from the ground, the falling meteors all seem to originate within the constellation. Leo is one of the largest constellations in the sky and one of the most recognizable, as the "pointer stars" of the Big Dipper are aligned in such a way that they point to it.
The brightest star in Leo is Regulus, situated at the front paw of the lion. Regulus is actually two stars, which can be seen from Earth through a pair of medium-magnification binoculars. Leo is home to multiple binary and tertiary stars and several variable stars. The closest of these is Wolf 359, which has been featured in science fiction shows "The Outer Limits" and "Star Trek: The Next Generation."
Killing the Nemean lion was Heracles' first labor, which he accomplished with his bare hands. Ancient Greeks believed that Zeus placed Leo in the sky in honor of his triumph.