Trivia Question - What was the first permanent major

Who knows the answer to this question?

WHAT WAS THE FIRST MAJOR PERMANENT ARCHITECTURAL STRUCTURE TO BE CONSTRUCTED IN THE U.S.?

I'm guessing it would have been a building in Philadelphia since that was initially considered to be the country's capitol before it changed to Washington, D.C.

Anyone know?

My curiousity was piqued after seeing the facade (and classical style) of the New York Public Library recently. I should know the answer to this question - I'm certain we must have at least skimmed this topic in my museum studies class but I have poor recall.

A lil bit of museum history and info on the American "father" of such (Peale's Museum and the Cabinets of Curiosity):

[link to en.wikipedia.org]