background bridge decay grunge industrial industry iron metal Portland rivet rivets rust steel Steel Bridge texture truss cables mesh movement shade shadows slats steel mesh strong sturdy sunlight suspension bridge swaying swinging swinging bridge wooden flooring blue column Coronado bridge flyover overpass roadway span traffic transport usa viaduct concrete river sky girder Incredible India India karnataka krayker Mangalore perspective railway rusty rusty bridge sepia track bay California city coast construction golden gate bridge landmark red San Francisco travel water park path strength support trail pedestrian posts protection railing rails rods safety suspension walkway waterway