In the study, there was a large bookshelf—so large that it attracted the attention of the international investigators who were searching the property. They had followed the collector home; they had a judicial order to search his house in a suburb of Buenos Aires. They were right to examine the bookshelf. It opened into a secret passage, and at the end was the room that housed the collection—75 astonishing artifacts from Germany’s Third Reich.

The collection of Nazi memorabilia included a bust of Hitler, a statue of the Imperial Eagle, and a medical device to measure the size of a human head, which was used in service of theories about race and head size. There were objects decorated with swastikas, including an hourglass, a knife, a box that held harmonicas meant for children, and another box containing a magnifying glass. One of the most important parts of the discovery is an image of Hitler holding a similar magnifying glass. (The photo has not been released to the public.)

This is a huge find, the largest collection of Nazi artifacts ever discovered in Argentina. It began after “illicit artwork” appeared in a gallery in Buenos Aires, the Associated Press reports. The name of the collector has not been released, but he is under investigation. Authorities believe that the objects may have originally belonged to high-ranking members of the Nazi party, who fled to Argentina after the fall of the Nazi regime.

The sale of Nazi memorabilia is restricted in some countries, and online auction sites have restricted the sale of such objects in part to depress the market for recreations. Argentinian anti-discrimination law restricts the sale and possession of such objects, too.