King's Landing Harbour
The Lannisters watch Myrcella depart on the boat to the south in episode 2x06 "The Old Gods and the New". Cersei watches Jaime return with Myrcella's body in episode 6x01 "The Red Woman". The Stark siblings get together one last time before they each head off on their own paths in episode 8x06 "The Iron Throne".
Goldcloaks throw one of Robert's bastards into the water in episode 2x01 "The North Remembers".