Underneath San Francisco's most iconic attraction is another historic landmark. The eerily fascinating mansion sits abandoned on Yerba Buena Island.

The original Bay Lights went up in 2013, and 10 years later, they went dark due to the cost of maintaining the lights being unsustainable. But this time around, the nonprofit behind the project is stepping it up after raising $11 million.

They’re back! Well, almost at least. Timelapse video captured by KRON4 shows testing underway for the newly reinstalled Bay Bridge lights (Watch in the player above). The lights went dark almost three years ago,