Pittsburgh's Civic Arena (later called Mellon Arena) was built in 1961. At the time it was the world's first and largest moveable dome. This vintage postcard from the early years features a view of the arena from the observation promenade deck atop the Gulf Building.
The venue was deemed an all-purpose sports arena, convention hall and auditorium-theatre, and was built at a cost of $22 million and was considered one of America's engineering wonders. The huge stainless steel roof, weighing more than 3,653 tons, was able to be rolled back in two and a half minutes for open-air events such as concerts and operettas. It was nicknamed the Igloo because it resembled one and because the Pittsburgh Penguins hockey team played there for so many years. It was finally demolished in 2012 for a more modern structure.