Martin M. Miles' photos with the keyword: Túnel romano

The Roman tunnel of Boca do Monte was built in the 2nd century by order of Emperor Trajan to divert the course of the River Sil and extract the gold deposited in the meanders of the old course of the river. It is dug in slate and was 120 metres long until 1934, but a flood of the River Sil in that year caused a large part of the tunnel to collapse, giving it its current dimensions: 54 metres long, 19 metres wide and an average height of 17 metres.