M44, the Praesepe or Beehive, is an open star cluster located halfway between Gemini and Leo.
It is easily visible to the unaided eye as a hazy 3rd magnitude patch. Galileo first observed it in a telescope as a collection of about 40 stars, and today's modern large telescopes reveal about 350 stars. M44 is about 577 light years away, and is about 400 million years old.