There is a loophole, in which it’s illegal to traffic certain cultural items within the United States, but exporting them is not prohibited. The Native American Graves Protection and Repatriation Act (NAGPRA), which was enacted in 1990, requires repatriation of sacred or culturally significant items to their respective tribes or lineal descendants. It also instituted procedures for when said items are inadvertently discovered in excavations on federal lands. However, NAGPRA does not apply internationally. – Hyperallergic