Riggs Library - Georgetown University. Washington D.C.
Someone once referred to architecture as 'frozen music.' This library is a cacophony. Equal parts steampunk and cast-iron victorian. All of it a wonder to behold. Until 1970, this was the main library on campus.
Spiral staircases that reach skyward like trumpet vines on a summer fence. The only problem with the Riggs Library is that you will forget what book you were looking for.