Black holes in my opinion are a result of what is known as anti matter, it is simply a huge collection of it.
some say black holes could be used to time travel into the past, not knowing how far however, as the destination time would be preset upon the formation of said black hole.
however it still raises a couple of issues, namely paradox, if someone were to travel into the past to stop themselves from commiting an act. they would end up never commiting the act and never traveling through time to begin with.
I also believe they have tremendous destructive power, as once a single atom of your body enters it, your entire being is whipped through at the speed of light, thus achieveing infinite mass and killing you instantly. it's a bit of a doozy to get around.
Just my 2 cents