The former Customs House (Aduana) is one of the most historically significant buildings in northern Mexico. Built in the nineteenth century to process the enormous cross-border trade along the Paso del Norte route, it was here that the Treaties of Ciudad Juárez were negotiated in May 1911 — the agreements that ended the Díaz dictatorship and ushered in the Mexican Revolution's political phase.
The building now operates as a free history museum covering the Porfiriato period, the Revolution, and the development of the border region. The collection includes documents, photographs, and artefacts from the treaty negotiations. Even visitors who don't read Spanish will find the building itself — and the weight of what happened inside it — worth the visit. The museum is a short walk from the cathedral.