Twice a year, in February and June near the island Chindo, is the third largest island in the archipelago Jindo in South Korea, there is a grand tide. This will open a natural bridge that connects the two islands (between about 3 kilometers) road width of 10-40 meters. Tides, and even reinforced tailwind, really can work wonders. Little over an hour, during which opened the way to the water, tens of thousands of people have time to make a little pilgrimage.
With this natural bridge Koreans tied its own legend. In ancient times the island Chindo terrorized the Tigers. All the inhabitants fled to the neighboring island, but they forgot the old woman Ppong. That begged the King of the Sea (of course, it was a dragon), and god took pity on the old lady. Marine King gave her good advice to go over the rainbow. Old Ppong obeyed, and in the morning before her parted the sea. So she was reunited with his family.