The Porte Collatice arch and the start of the road to Rome

Why do we keep the broken bits? Because they tell us where the road to Rome actually started. In the 3rd century, this wasn't just a door; it was the Porte Collatice, a massive monumental arch marking the southern entrance to Durocortorum. It was the starting point for the road heading straight for the capital.

It had a bit of a makeover over the centuries. By the time of the barbarian invasions, it was swallowed into a new fortified wall. They even scavenged some of its stones to build those defenses - a bit of architectural recycling with a dark edge. It eventually lost its importance when the city walls were enlarged to the south, as it was used to access the suburban churches.

What happens to a gate when it's no longer needed? It gets demolished. Most of the arch was destroyed in 1753 during water works, leaving only fragments behind. Today, you can still see a vestige of a pile near the refectory of the Collège Université. It is a small piece of stone that remains as a fragment of the ancient structure.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons