The 63 Building, officially called 63 SQUARE, is a skyscraper on the island of Yeouido, overlooking the Han River in Seoul, South Korea. At 249.6 m high, it was the tallest building outside North America when it was opened on July 27, 1985, and it is the second-tallest gold-clad building in the world after Grand Lisboa in Macau. It stood as South Korea's tallest buildin…The 63 Building, officially called 63 SQUARE, is a skyscraper on the island of Yeouido, overlooking the Han River in Seoul, South Korea. At 249.6 m high, it was the tallest building outside North America when it was opened on July 27, 1985, and it is the second-tallest gold-clad building in the world after Grand Lisboa in Macau. It stood as South Korea's tallest building until the Hyperion Tower surpassed it in 2003, but remained the country's tallest commercial building until the Northeast Asia Trade Tower was topped-out in 2009.