"We had 10 million hits by the hour of interested Internet users across Europe and that led to the fact that at 11:30 am, we had to take temporarily the site down to double the computer capacity," spokesman Martin Selmayr said.
The site, which allows access to more than two million digital objects like films, paintings, photographs, sound recordings, maps, manuscripts, newspapers, documents and books had only been open a short time.
Selmayr said six computer servers, instead of three, were now in action.
"It is now up and running again," he said. "We hope we will be able to survive the next storm of interest."
With 14 staff members and at an annual cost put at around 2.5 million euros (3.15 million dollars), Europeana - which can be found at www.europeana.eu - currently has around two million digital items online.
By 2010, the date when Europeana is due to be fully operational, the aim is to have 10 million works available.