SOUTH BEND, Ind.-- Power has been restored to downtown after nearly 3 days in the dark.

On Thursday night the underground power grid caught fire and it destroyed a large part of the system.

AEP Crews from Indiana and Ohio worked around the clock through the weekend to get the lights back on.

The President of Indiana Michigan Power said they will be launching a full scale investigation to find out how the outage happened.

Paul Chodak said, “ It was a pretty significant fire that we had in there so it took some time to replace all that charred cable and pull it all out.”

On Sunday AEP workers went store to store flipping breakers and turning on the lights.

Chodak said, "They’ll have to turn their generators off, and then close the breaker to get into the system to come back online which means it will interrupt their power momentarily to make that switch.”

The manager at Café Navarre said this is usually their biggest weekend of the year because of Notre Dame and Saint Mary's graduation ceremonies.

Dan DeMeester said, “Financially it wasn’t where we wanted to be, we still did very well. We probably netted about $40,000 in sales between the two nights.”

Café Navarre rented two generators to stay open for the weekend.

DeMeester said, “It’s a beautiful sight not coming into work and seeing generators pumping out diesel fuel and all the exhaust fumes."