wooden footbridge crossing marshland in vila nova de gaia, portugal, on a sunny afternoon

birdwatching biodiversity preservation conservation observatory destination perspective environment tranquility exploration footbridge background marshland afternoon cityscape boardwalk landscape ecosystem discovery adventure crossing portugal estuario contrast outdoors distance reserve esturio wetland skyline sunrise morning tourism walkway horizon estuary natural wooden nature golden summer scenic travel beauty sunny porto douro local urban rural light water river peace vila nova gaia long bird city hour path