An underwater billboard near Sweden's shores inviting divers to book a week off at Hurghada in Egypt through the Ving travel agency.
Underwater billboards from the 1950s promoting a seafood chain in Seattle -- possibly a giant hoax but no less awesome. Read the story reported by Seattle's newspaper, see videos, view possibly original maps, and pics.
In a swimming pool in Malaysia.
An underwater billboard for a Sanyo camera -- it becomes visible when the tide goes down.
A recruitment poster for the Navy.
And for scuba lessons.
And we are finishing on this optimistic note.