With more than 2,000 years of history, Paris is an architecture enthusiast's paradise. From its fabled arches and Beaux Arts institutions to its Gothic cathedrals and luxe gardens, the city is a veritable time capsule, filled to the brim with awe-inspiring historic sites and landmarks. While many travelers can easily identify some of Paris’s most famous monuments, it takes some know-how to discern just which sites are the oldest. We’ve rounded up five of the longest-standing structures for those vacationers looking to add an extra layer of history to their experience in the City of Light.