The famous dome of St Peter's was left in darkness late on Wednesday to allow tests to be carried out on special LED lighting on the basilica ahead of the Jubilee Year of Mercy, Vatican Radio reported on Thursday.
"The unusual sight was not due to technical problems or security concerns, but was part of a test ahead of a light show – called 'Fiat Lux' – being organized for the Jubilee of Mercy," Vatican Radio said.
The tests gave tourists and journalists a rare image on Wednesday night and Thursday morning: the famed Bernini colonnade shining brightly on its own, while St Peter's usually dome was obscured in the background.
Power company ACEA are testing the LED lighting for St Peter's dome and the Via della Conciliazione, which leads to the Vatican to make sure it is ready for the eve of the Jubilee on 7 December,” said a Vatican spokesman Father Ciro Benedettini, cited by Vatican Radio.
Over 30 million pilgrims are expected to visit Rome during the Jubilee Year of Mercy, which Pope Francis has declared will begin on 8 December.
Italy raised its security levels after the deadly Islamist terror attacks in Paris on 13 November and days later the government said had received a warning from US authorities of possible attacks on targets including St Peter’s Basilica in Rome.