A maritime tunnel known as the Rove Tunnel, located in southern France, was constructed to link the port of Marseille to Berre Lake, a large inland water body near the city. The tunnel, spanning 7,120 meters, was completed in 1927 after more than two decades of construction. It was designed to allow the passage of large barges and ships, a feat that was considered highly advanced for its time. The tunnel was part of a broader effort to strengthen Marseille’s role as a key Mediterranean port by improving transportation routes and facilitating trade. The construction of the Rove Tunnel was a massive undertaking, involving hundreds of workers who faced difficult conditions, including unstable rock formations and persistent humidity. The project was seen as a significant achievement in civil engineering, comparable to other major infrastructure projects across Europe. However, in 1963, a partial collapse of the tunnel’s vault rendered it impassable. The damage split the tunnel into two disconnected sections, and authorities decided not to repair the structure, leading to its abandonment. After the 1963 collapse, the tunnel was no longer used for navigation. Changes in the economy and the development of new port infrastructure further reduced the need for the tunnel, sealing its fate. Today, the two massive entrances remain visible—one near Marseille and the other near Berre Lake—while the interior is largely inaccessible. The collapsed section has left the tunnel in darkness, filled with moisture and sediment, transforming it into a strange, almost otherworldly space. Despite its historical significance, the Rove Tunnel has not been the subject of any major rehabilitation efforts. Some groups interested in industrial heritage have expressed interest in the site, but no comprehensive restoration or preservation plan has been implemented. The tunnel now stands as a forgotten relic, accessible only in appearance but completely off-limits to the public, a silent reminder of a bygone era of engineering ambition.