In a heartbreaking and poignant moment, Hal Jordan visits the ruins of Coast City, destroyed during the Return of Superman. Struggling with his grief, Hal uses his power ring to momentarily recreate the city and its inhabitants.
Unfortunately, this act draws the attention of the Guardians, and they want to punish Hal for it.
This, of course, kicks off Emerald Twilight, resulting in the destruction of the Corps and Hal's fall from grace.
In the years since, it's all been overturned. However, the green image of Hal's home city remains a haunting one.