Mute swans ("Cygnus olor"), Mallards ("Anas platyrhynchos") and Black-headed gulls ("Chroicocephalus ridibundus", Syn. "Larus ridibundus"), view across Danube river towards Donauinsel, Donau City with DC Tower 1 (height: 220 m) and Donauturm (height: 252 m) covered in low Stratus clouds; Vienna, Austria.