Mass Effect part 2

In the second episode, Captain Shepard Conducts demining the spaceport Eden Prime
And also in the process of evacuation comes into contact with the with an artifact of a mysterious civilization
As a result, he sees a mystical experience of the future
The mysterious civilization of the gods was destroyed 50,000 years ago.
Why, at the peak of its power, this civilization disappeared, leaving behind a transport infrastructure throughout the Galaxy.