The Vatican Museums attracted just over five million visitors in 2011, its highest number ever, according to the director of the museums Antonio Paolucci.

Paolucci said that the wear and tear of almost 5.1 million visitors poses a challenge for the upkeep of the museums' marble floors and mosaics, while the humidity and dust generated have a negative impact on the frescoes and plasterwork.

Last year the museums expanded their opening hours and reintroduced Friday night openings. In 2010 there were 4.7 million visitors.

Paolucci said that the Vatican Museums are now among the most-visited museums in the world, such as the Louvre in Paris (8 million visitors each year), the British Museum in London (5.8 million visitors in 2011) and New York's Metropolitan Museum of Art (5.6 million visitors last year).