Starting from the Sewer Museum, this walk led by archaeologists explores the Senne. How did the river cross Brussels? What traces did it leave in the Pentagon? The visit leads through excavated sites, ancient remains and emblematic places that bear witness to the presence of this river, now largely underground. It reveals the urban and economic history shaped by a watercourse essential to the development of Brussels. The Sewer Museum is presenting the temporary exhibition “Back on Senne”, which highlights the river’s history, its vaulting, its gradual rediscovery and contemporary issues surrounding its place in the city. The exhibition explores the Senne as a vanished yet still living landscape. The museum’s permanent collection is also freely accessible, offering a broader view of Brussels’ sewer network, how it works and how it has evolved over time.