Once upon a time kids, telephones were attached to to wires and everyone had to carry a sign like this around everywhere they went to stop others tripping over the cables...
Actually, no. Thanks to Duncan Young for this photo from the front at Dartmouth. It's a rare survivor and actually a message to boats to be careful where they drop anchor for fear of this dragging and hauling up the lightly buried cable heading out to sea.
The sign might be old and showing the effects of being near the sea with rust streaking from the letters, but the cable still exists. Cables still exit the town even today, some being laid in the 1980s.
I've trimmed this a bit to avoid the picnicing couple on the bench beside it, but I'd reckon on this being about 12 foot high. It would certainly add an interesting feature to a dockside model.