Visit London and See the Seals? Many Marine Mammals Sighted in the Thames Don Melvin [CNN] September 3, 2015 — No Comments ↓ Forget Big Ben. That’s old hat. Maybe the city’s new tourist slogan should be this: Visit London and sea the seals. No guarantees, of course. But if you spot a seal, or maybe a dolphin, you won’t be the first. Click here to read more.