Bodleian Library in Oxford

You're standing at the Bodleian Library, the main research library of the University of Oxford. Students just call it the Bod. Look at the tower above the main entrance. That's the Tower of the Five Orders. Count the columns from bottom to top and you'll find all five classical styles stacked on top of each other, from Tuscan and Doric at the bottom to Composite at the top. In 1769 an astronomer watched Venus cross the face of the sun from this very tower.