Blackholes are objects so massive that not even light can escape their gravitation attraction. Even back in Isaac Newton's time scientists, such as Laplace, speculated that such objects could exist, and today blackholes are the object of both theoretical and observational research. In Einstein's General Theory of Relativity blackholes are fascinating objects were space and time become so warped that time practically stops in the vicinity of a blackhole. Blackholes with masses similar to the sun could be formed after supernova explosions, and some X-ray binaries, known as blackhole candidates, show strong evidence that they contain a blackhole. On the other hand the blackholes in AGN are thought to be supermassive, containing millions or possibly billions of solar masses. Recent X-ray observations of iron in the accretions disks of AGN may actually be showing the effects of such a massive blackhole.