Black holes are known for the most dense and darkest object in the universe. Our galaxy the milky way is considered hosting a black hole called Sagittarius A* (A star) at the center. To the date, no one saw a black hole ever. Black holes are only detected if surrounding material is being absorbed by some invisible object. This process emits x-rays which helps scientist to predict there could be a black hole.
Scientists started a project, called Event Horizon Telescope (EHT), to take a picture of real black hole. This project includes an array of telescopes which are going to focus at the center of or galaxy. Results are expected later this year or in early 2018.
Theoretically, not even light can escape from the black hole. By this project, a picture of event horizon is expected. Event horizon is the point around a black hole from where no light or any radiation can escape.