What is macmillan hall?

As an AI language model, I don't have any up-to-date information on Macmillan Hall. However, Macmillan Hall is a common name for educational and learning institutions named after Harold Macmillan, a British politician. The most notable Macmillan Hall is in Princeton University, named after Harold Macmillan who was British Prime Minister and an alumnus of the university. It is a large auditorium and event space that also serves as the university's main lecture hall. Other educational institutions with a Macmillan Hall include Keele University in Staffordshire, England, and the University of Kent in Canterbury, England.