Royal Naval College from Island Gardens on the Isle of Dogs.
It's not known how the Isle of Dogs got its name, although it's probably an association with hunting dogs, Royal hunting dogs from Greenwich or just retrievers used in hunting ducks on the formerly marshy "island". Its also possible "dogs" is a corruption of "ducks" itself. It's interesting that "Canary Wharf" was named after its trade connections with the "Canary Islands" which were in term named from the latin for dogs (canis) so common there.