VATICAN CITY — Michelangelo's Sistine Chapel ceiling frescoes turned 500 on Wednesday with the Vatican warning it might eventually limit visitors to protect one of the wonders of Western civilization.

In 1512, Pope Julius II said an evening vespers service to inaugurate the room where Michelangelo toiled for four years, much of it on his back, to finish his ceiling frescoes. Now, about 5 million people, as many as 20,000 a day in summer, visit the chapel every year.

Last month, an Italian literary critic wrote a letter in a major Italian newspaper denouncing the behavior of crowds visiting what is technically a sacred place. Tourists, he said, "resemble drunken herds" as they unwittingly risked damaging the frescoes with their breath, their perspiration, the dust on their shoes and their body heat.

At a vespers service Wednesday night to commemorate the event in the same room 500 years ago, Pope Benedict seemed to agree on the need for more contemplation when in the chapel.
