The world’s tallest building, Burj Khalifa (formerly Burj Dubai), officially opened Jan. 4 in Dubai, United Arab Emirates.

Architect Adrian Smith, who designed the building while at the Chicago office of Skidmore, Owings & Merrill, attended the opening. Smith left SOM in 2006 to start his own firm, Adrian Smith+Gordon Gill Architecture.

The Burj Khalifa’s official height was announced at 828 meters, or 2,716.5 ft.

“It was the culmination of many years of work and one of the most thrilling moments of my career,” said Smith.

With completion of the Burj Khalifa, Smith has designed three of the world’s 10 tallest completed buildings: Burj Khalifa in Dubai (#1), Trump International Hotel & Tower in Chicago (#7, at 1,388 ft) and Jin Mao Tower in Shanghai (#8, at 1,381 ft), according to the official rankings of the Council on Tall Buildings and Urban Habitat.