Low level languages allow you to interact with your hardware and operating system in pretty much any way you wish, at the expense of safety. It is very easy to write low-level programs that crash in mysterious ways or, worse yet, damage your system. Nonetheless, they are necessary for coding the nitty-gritty of OperatingSystems and some other "systems level" software. Be sure to read LowLevelMyth if you think that this makes them the language of choice for everything.
