C53 (NGC 3115)

Lacking spiral arms but boasting a galactic bulge and prominent disk, lenticular galaxies like Caldwell 53 are intermediates between the more familiar spiral and elliptical galaxies. This galaxy, like most of its kind, hosts an elderly stellar population and has used up nearly all of its star-forming material. C53 is perhaps most notable for the supermassive black hole that lurks at its center; astronomers estimate that it has a mass roughly one billion times the mass of our Sun. This means C53 hosts the closest billion-solar-mass black hole to Earth.