Tunnel of La Engaña Curiosity · Merindad de Valdeporres, Las Merindades, Burgos Almost seven kilometres of railway tunnel bored beneath the hills of El Somo for a train between Santander and the Mediterranean that never ran; the Trespaderne-Cidad line operated from 1930 and closed in 1985. Photo: Goldorak (CC BY-SA 4.0) What to see and do in Merindad de Valdeporres