They arrive ravenous. They leave bloated.

It's essentially a weeklong all-you-can-eat seaside seafood buffet on a direly replenishing leg of a super-epic cross-continental sky marathon.

Bar-tailed godwits stop over on sojourns from New Zealand to Alaskan breeding grounds. Red knots flutter in on journeys from Kiwi country to Siberia.

The spectacle in turn brings seasonal flocks of birdwatchers, naturalists and photographers to the Yellow Sea's shoreline. About 37,000 visitors took in the marvel in 2014.

Two-story log-cabin viewing towers stand watch along boardwalks.

Group packages booked through China's largest online travel agency, Ctrip, tripled this year for the week-long National Day Holiday, starting Oct 1, says the company's publicity director, Peng Liang.

Photography tours lasting about four days ranked among the most popular.

June to October is the best time to visit, Peng says.

Peng recommends local aquatic fare and ethnic Korean barbecues.

Dandong's chilly oceanfront is said to make seafood particularly delightful. And the Yalu River that ejects into the ocean hosts about 90 fish species, the local government says.

The area also sires hundreds of strawberry varieties, largely employing natural farming methods.

It's a truly sweet point of pride that stains fingers crimson.

Again, it's worth pointing out Dandong is, in most people's minds still a red, rather than green, destination. And that's likely to stick for some time.

But, in an almost alchemic sense, visitors may come for the red and stay for the green, conjuring gold in Dandong.