Located in the constellation Cepheus near the border with Cassiopeia, the Cave Nebula (Sh2-155 or Caldwell 9), is a dim and very diffuse bright nebula within a larger nebula complex known as Cepheus B. This complex contains also LDN 1216 - a large dark nebula above Sh2-155 and VdB 155 - the blue reflection nebula just right of LDN 1216.The stars of this region are members of the Cepheus OB3 association. They are very young, less than 100000 years old. A star formation is occurring within Cepheus B and is particularly evident within the dust clouds of the Cave Nebula.