A close-up of the distinctive hanging lights in the nave of St. Michael's Cathedral circa 1930. See a wider view of the nave and sanctuary with commentary over at Vox Cantoris. Compare the current hanging lights here.
The knowledge derived through faith must not be considered less certain because its objects are not seen; for the divine light by which we know them, although it does not render them evident, yet suffers us not to doubt them. For God, who commanded the light to shine out of darkness, hath himself shone in our hearts, that the gospel be not hidden to us, as to those that perish.
– The Catechism of Trent