Musing Monday's - Book Length

Musing Monday's is hosted by Miz B at Should Be Reading. This week’s musing asks:


What is the longest book you have ever read? How long did it take you to read it?

I'm not entirely positive about this answer.  I'm going to guess the later books in the Harry Potter series, though.  I remember the seventh book being near 800 pages and I think the sixth was just over 700.  I read these books within a few days of their original release dates (and a couple of times since) - so, fairly quickly.