Some of the most iconic and curious moments in Olympic history, from pictures of the first modern-era games in Athens in 1896 to a sack race in St. Louis, Missouri, eight years later, have now been archived. Sitting in a basement at the International Olympic Committee's (IOC) headquarters in Lausanne, Switzerland, some 33,000 hours of video, 500,000 pictures and 2,000 documents, among other materials, risked decay and being lost forever. But after a seven-year and 30 million euro ($33 million) conservation project involving experts from across the globe, the IOC has rescued much of its precious audiovisual archive.

"There was an urgency to save this legacy," said Philippe Laurens, an official with the IOC's Patrimonial Assets Management (PAM) program, which spearheaded the project.

When the preservation effort was launched in 2007 under former IOC president Jacques Rogge, the organization discovered that a large portion of its archives faced destruction. Faded photographs were deteriorating and some films were being destroyed by the so-called "vinegar effect," where chemicals in the films combined with moisture to cause corrosion. While some of the video material remained in good condition, the hardware needed to play it had become obsolete, meaning the video needed to be reformatted to make it compatible with modern devices.

A team of archivists first tried to identify all the available material, a job estimated to have taken 100,000 hours of work, which led them to uncover images that had previously been unpublished.

The group found a long tracking shot of the Eiffel Tower taken during the 1900 games in Paris, and spectacularly, footage of the victory lap Greek runner Spyridon Louis took after winning the marathon in the 1896 Olympics in Athens.

The IOC worked with experts from Switzerland, France, Canada, the U.S. and Thailand to document and repair the archives. "Every day, between 40 and 125 photos and between 15 and 20 hours of recordings were treated," Laurens said. Some of the material required highly specific attention, like 400 hours of footage on 16 mm and 35 mm film that had to be recopied onto new film to be preserved for another century.

In late 2012, the basement of the IOC headquarters that housed the archives flooded following heavy storms, raising fears that the project had suffered an unexpected setback. But heavy storage safes protected the material from water damage and the restoration work continued.

The salvaged material includes audio recording of Olympic founder Pierre de Coubertin and scenes that are unlikely to be repeated at the Olympics again. In one such image, two wrestlers are shown grappling at the 1912 games in Stockholm, with a referee in the background wearing a sun hat and a trench coat. The IOC has decided to make the material accessible to researchers and journalists who cover the games. "It is incumbent upon us to carry on the cultural heritage of more than a century of Olympic history left to us by our ancestors," said IOC Director-General Christophe De Kepper. "The legacy of the IOC can now withstand the test of time."

The IOC will for its conservation efforts receive an award at the prestigious International Broadcasting Convention awards in September. But officials in Lausanne know that the work of preserving the history of the games will continue indefinitely.

The summer 2016 Olympics in Rio de Janeiro are expected to generate another 3,500 hours of video and an additional 40,000 pictures.