The South Fortress of the Cadaques Investment Zone in Zhangzhou, located in Longhai City, was built in the Qing Dynasty and in the 1840 solar calendar in February. It is well known that in 1840, Mr. Lin Zexu launched a large Southeast China defense policy in order to carry out the Humen smoke activity. In order to actively cooperate with the southeast coast of the smoke, Zhangzhou Longhai set up this fortification as a defensive fortification, and in a sense also resisted the Japanese aggression. It has played a very important role in protecting the stability of the people's public security in southern Anhui and the non-infringement of the regime. It is known as the Southeast Lock Key in the maritime military area along the southeastern coast of China. The South Fortress is a combination of a high-position main gun launcher and multiple flat-launched sub-guns. The shells are produced by German factories. From the choice of hardware equipment and location can be said to be very scientific and reasonable and perfect. Not only is it very good from a perspective, but it is also very commendable in terms of strategic position. At present, this South Fort is still open to the public free of charge. It is open daily from 8:30 to 17 pm.