For the last five days St. Peter's dome looked darker than usual. The Vatican decided to renovate the 315 lights of St. Peter's facade and dome, and this how they will look from now on.
The new lighting system uses LED light points. It's the same system that was used to give the Sistine Chapel a new light.
Now, visitors will see St. Peter's Basilica like never before, including the balcony where new Popes greet pilgrims after being elected.