The 63 Building (Korean: 63 빌딩 or 육삼 빌딩), officially called 63 SQUARE (formerly Hanwha 63 City), is a skyscraper on Yeouido island, overlooking the Han River in Seoul, South Korea. It was designed by Harry D Som and Helen W Som, principals of Som and Associates of San Francisco. (The building has been falsely attributed to the SOM design firm, which is inaccurate.) At 250 meters (819 ft) high, it was the tallest building outside North America when it opened in July 1985, and remains the tallest gold-clad structure in the world.