Dirt, dust, and candle smoke covered the frescoes on the ceiling of the Sistine Chapel in Rome for centuries. To make the needed repairs, a team of art restorers worked on the frescoes for fifteen years to remove the age-old grime. Using sophisticated photographic equipment, spectrometers, and computers, the group located the areas needing the most work. Once the restoration was complete, the ceiling showed the brilliant colors and depictions created by Michelangelo in the 15th century. To ensure the long- lasting effects of the restoration work, a special air filtering system, like that used by NASA on the space shuttle, was installed to monitor the amount of humidity and dust.