The concept of racism has changed over time. Historian Christian Geulen explains that the term “race” is rarely still used today. Racist hierarchies dating back to around 1800 were used to justify slavery and colonialism. But racism persisted even after the Enlightenment, often as an ideology of superiority. Today, racism manifests in more subtle ways, often for instance through cultural boundaries. Geulen emphasizes that we must remain vigilant when it comes to recognizing new forms of racism.