Ayers Island Nuclear Power Plant was located on off the shore of Metropolis.
Darkseid sought to destroy the nuclear power plant as a prelude to his invasion of Earth. To this end, he sent Bruno Mannheim and a group of parademons to sabotage the plant's cooling system before setting its reactor to explode. This phase of the plan went off without a hitch, and also served to dispose of Mannheim when Darkseid betrayed him and left him to die on the island.
After the plant exploded, its nuclear reactor began burning through the remains of the island, making its way towards the Earth's core. Professor Hamilton predicted that the reactor's impact with the core would create a number of fire pits all over the planet, effectively turning Earth into a second Apokolips. Superman quickly moved out to avert this crisis, briefly clashing with Darkseid's minion Steppenwolf on his way to the island. After defeating Steppenwolf with the help of Dan Turpin and the Special Crimes Unit, Superman managed to defuse the reactor by flooding an underground cavern in its path, cooling the reactor down when it fell into the seawater.