The Grand Tian Chi, generally known as Fan Jia Barrage, is the largest of the 14 barrages that were built in the Diaoyucheng City. It is recorded that the Grand Tianchi pond was built by damming the natural gully in the West City. Yet, it cannot be called huge in the modern sense, for the pond is only a little more than 500 paces in circumference. However, with the spring water gushing into it all the year round, it never runs dry, thus making an ideal place for fish and other aquatic lives to live there. It is said that in July, 1259 during the Southern Song Dynasty, Zhang Jue, vice-general of the City, asked the people to catch two huge fish, with each weighing over 15 kilograms. With the fish, they baked over a hundred fish meat pies and sent them to Mongke Khan as a “gift”. Together with the “gift” was a letter written by Zhang, in which there was one line that read, “Have you ever enjoyed such delicious fish meat pie recently, you guys from the north? Even if you stay here for ten more years, I’m sure you’ll disappointedly find this city is still in our hand.” Up to today the Grand Tian Chi has been playing an important role in water conservation and irrigation.