Almawashi - a huge livestock ship off Gibraltar
Used to seeing cruise ships, but this looks like someone parked a tower block in the bay. To get an idea of the scale, if you look at the larger versions of the image, you can see some crew standing at the back off to the right (ahem, the starboard side of the stern).
According to the Gib Port Authority, the 30,435 tonne ALMAWASHI is on its way from Tartous (Syria) to Montevideo (Uruguay) under a Panama flag. Formerly registered under a Kuwait flag. The World Shipping Register lists it as a livestock carrier built in 1973, call sign 3EDN7.
The smaller ship is the Aegean Daisy, call sign ZDFQ5, a chemical tanker carrying a Gibraltar flag, built in 1978.