Drawing on archival sources, I argue that the 1962 Seattle World’s Fair (also known as Century 21) was an important source for Thomas Pynchon’s surreal depictions of the Raketen-Stadt in Gravity’s Rainbow. Accounts of the influence of Seattle on Pynchon have been limited to his work as a Boeing technical writer, and Century 21 goes unmentioned in work on the novel’s allusions by Steven Weisenburger and others. Pynchon responds throughout Gravity’s Rainbow to Century 21, particularly its Cold War views of space-age futurism and nuclear weapons. I draw new connections between the angel of Lübeck and John Glenn’s World’s Fair appearance; aspects of the Raketen-Stadt and the fair’s US Science Pavilion; and Pynchon’s many towers and elevators and that signature feature of Century 21, the Space Needle. The conclusion attends to the fair’s traces in Against the Day and Bleeding Edge, demonstrating Pynchon’s nearly career-long fascination with the event.