億載金城又稱「安平大砲台」，但一般人仍習稱「億載金城」。清同治13年(1874)，清政府派遣沈葆楨為欽差大臣，渡海來台籌辦海防。沈氏勘定安平形勢險要，乃奏請在此建造西式砲台一座，延請法人設計。砲台在光緒2年(1876)完工。沈葆楨親題「億載金城」、「萬流砥柱」八字，分置內外門額，氣勢雄渾，護土不讓。目前放置在砲台內供人參觀的大砲，是民國64年(1975)台南市政府推動觀光年，為紀念砲台創建一百週年特別仿製的成品。

Eternal Golden Castle (Erkunshen Cannon Fort) also called Anping Big Cannon Fort is commonly known as Yi Tsai Ching Cheng, literally meaning “Eternal Golden Castle.” In the 13th year of the Tung Chi reign of the Ching dynasty (1874), Shen Pao-Chen was appointed as an imperial officer to engage in the buildup of Taiwan’s naval defenses. After his observation and survey of Anping’s geographical environment, he proposed to the emperor that a western-style French-designed cannon fort should be built here. The construction was completed in the second year of the Kuang Hsu reign of the Ching dynasty (1876). Written and autographed by Shen Pao-Chen, the eight Chinese characters “Yi Tsai Ching Cheng” meaning “Eternal Golden Castle,” and “Wan Liu Ti Chu” meaning “Pillar Impregnable” are inscribed respectively on the outer and the inner walls, illustrating the impregnable and unyielding characteristics of the fort. The big cannons on display inside the fort are imitations created in 1975 by the Tainan Municipal Government to mark the 100th anniversary of the fort and to promote tourism in the city.