Abstract
First appearing in the theoretical field, the black hole is now part of the standard astrophysical bestiary. After introducing the concept of the black hole within the framework of the relativistic theory of gravitation - general relativity - we will review the main properties of these objects. We will then discuss the growing body of observational data on both electromagnetic and gravitational waves. The former have recently led to images of the immediate environment of a black hole, while the latter allow us to probe the dynamics of these objects. In both cases, new tests of relativistic gravitation become possible.
