Fish traps or weirs are one of the oldest methods developed for catching fish. These were usually built of stones or wooden posts and utilizes the tides to trap fish within the walls. High tide brings in fishes in the walled area and when the tide ebbs away, the fishes remain trapped in the weir and become an easy catch. Studies indicate that stone fish weirs were used around the world as early as the Neolithic age, including southern pacific islands, Asian countries coasting the pacific ocean, and even Finland and Australia. In the Penghu archipelago, in west of Taiwan, local fishermen have been constructing weirs by means of stacked stones for the past 700 years.

Penghu has over 570 stone fish weirs, but the most famous of them is the Twin-Heart Stone Weir in Chimei Township. Built out of basalt and coral reef, the weir, as its name suggests, resembles two hearts spooning top to bottom. Because of this unusual shape, the Twin-Heart Stone Weir draws a large number of tourists especially romantic couples and newly weds.

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