Review of detailed designs, and construction inspection. It is the largest tunnel in Colombia (9.7 km). Starting from the municipality of Cañas Gordas (Department of Antioquia) for a length of approximately 18.3 km, consisting of 973 m of bridges, 4.97 km of open-air roads and 12.3 km of tunnels, of which 9.75 km corresponds to the Toyo Tunnel.