sentences:  Due to the containment of the Rhone and Bietschbach rivers, the draining of the swamps in 1865–1885 and the construction of the Lonza Entsumpfungs canal in 1920, the valley opened up for agriculture.Raron evolved in the second half of the 20th century into a modern industrial and small business town.Residential and commercial buildings spread out across the valley floor.