The chimney has historically been used in burning the ballots for the conclave that will elect a successor to late Pope Francis.
The secret meeting begin on May 7, 2025 with the sequestered cardinals using the chimney to tell the outside world whether they have elected a new leader of the 1.4 billion-strong church.
Black smoke will signify no decision, white will announce that the 267th pope has been elected. The workers attached a rust-coloured pipe above the terracotta tiles of the roof of the 15th century Sistine Chapel, which is known for its frescoes by Michelangelo.
The chimney is clearly visible from the nearby St Peter's Square, where thousands are expected to gather during the conclave to see how the secret balloting is progressing.
---Reuters---