From the first Ferris Wheel, the first banana split, the first baseball stadium, the invention of Bingo and the first Big Mac to Mr. Yuk and the steepest public street in the US, Pittsbrugh ranks number 1 in a lot of things and a lot of things were invented in Pittsbrugh.
A more complete list can be found here: https://backpackandsnorkel.com/USA/Pittsburgh/Firsts/