So, what am I talking about? I am talking about what appear to be holes but what are actually "Dark Nebulae". Doesn't this picture look like a hole in the star filled sky?
Following are five more examples of dark nebula. The first one below looks to me exactly what it is, a cloud of gas. It would be hard to tell exactly what the other four are. You have to admit that they are all beautiful and unique.
I have saved the dark nebula (or absorption nebula) that seems to be everybody's favorite and most people do recognize it as the Horse Head Nebula. It does look like what its name describes: