Restoration of the Sistine Chapel frescoes smoke and exhaust fumes of the city, being "much dirtier than the ceiling proper". The building was a little unstable and had already shifted considerably prior to Michelangelo's work of 1508, causing cracking of the ceiling, the crack in the "Judith" pendentive being so large that it had to be filled with bricks and mortar before painting. The upper part of the ceiling provided Michelangelo an irregular surface due to cracks and water seepage. Continued ingress of water from the roof and from unroofed exterior walkways above the ceiling level had caused seepage which carried down salts from the building
Sistine Chapel ceiling God, he was swallowed by a "mighty fish". He spent three days in its belly and was eventually spewed up on dry land where he went about God's business. Jonah was thus seen as presaging Jesus, who having died by crucifixion, spent part of three days in a tomb and was raised on the third day. So, on the ceiling of the Sistine Chapel, Jonah, with the "great fish" beside him and his eyes turned towards God the Creator, represents a "portent" of the Passion and Resurrection of Christ. The Jonah figure placed right over the altar activated the Passion