Black and white lantern slide of The Janella Valley - Visit to Madeira. Part of Box 125 - Madeira. Boswell Collection. Ribeira da Janela is a civil parish (Portuguese: freguesia) in the municipality of Porto Moniz in the Portuguese islands of Madeira. The ravine, Ribeira da Janela, meanders through the parish from Paul da Serra (springing from the plateau at around 1,420 metres altitude) and flows at various intervals along the water course.[2] The valley cut by this ravine is one of the longest in Madeira. Forests dominate the northern and the western parts of the valley and while brush permeates in the remaining areas.