The basilica, erected over the tomb of St Peter the Apostle, is the largest religious building in the world, the fruit of the combined genius of Bramante, Raphael, Michelangelo, Bernini and Maderna.

One of the most significant restorations is of Bernini's Baldachin, a canopy that sits atop the tomb of St. Peter. "Before, you have to imagine, I think, it was very black. And now we can admire ...

But when descendants of the 17th-century cardinal Flavio Chigi had thick layers of dark overpainting removed, they realised they owned an extraordinary sculpture by Gian Lorenzo Bernini ...