Golana was an inhabited planet in the Alpha Quadrant. This was the home of a Bajoran colony since the beginning of the 24th century. Archaeologists from the Bajoran Archaeological Institute were studying the ruins of a technologically advanced civilization that had had gone extinct over two thousand years before.
In 2374, an active time portal from this lost civilization was accidentally discovered in a cavern. The portal sent Molly O'Brien three hundred years into the past, when the planet was uninhabited. She was eventually recovered safely. (DS9: "Time's Orphan")