More than twice the number of hits than anticipated has crashed Europeana - the new online library - just hours after its launch.
The project offers free online access to content from 1000 of Europe's most prestigious institutions including The British Library.
It was receiving 10 million hits per hour straight after launching.
But it was thousands of people all searching for information - whether pictures, photos, films, books, maps and manuscripts - relating to the Mona Lisa, which brought the site to a standstill.
Users clicking on Europeana.eu are now getting a message saying the site is "temporarily not accessible due to overwhelming interest after its launch".
It adds: "We're doing our utmost to reopen Europeana in a more robust version as soon as possible. We'll be back by mid-December".
A spokesman for the European Commission adds: "It confirms it's [the project's] worth doing, European culture is more popular than we had anticipated in our wildest dreams".