Frank Lloyd Wright’s Solomon R. Guggenheim Museum is still a shock on Fifth Avenue. The architecture declines to fade into the background or get old, never mind the building turns 60 this month.

Happy birthday to one of modern architecture’s transcendent achievements! Its spiral ramp has defeated generations of curators trying to figure out how to install exhibitions on it. The building has gone through ham-fisted additions, hostile restorations, lousy paint jobs and too many bad imitations to coun t.

But it endures everything, a testament to what the critic Ada Louise Huxtable once called its “unified space and structure.”

Neither Wright nor the man who commissioned him to design the building, Solomon R. Guggenheim, saw it finished. Guggenheim had died a decade earlier, Wright shortly before the building opened. He was 91.